Testing the Canon R6 for Astrophotography


In an extensive technical blog, I put the Canon R6 mirrorless camera through its paces for the demands of astrophotography. 

Every major camera manufacturer, with the lone exception of stalwart Pentax, has moved from producing digital lens reflex (DSLR) cameras, to digital single lens mirrorless (DSLM) cameras. The reflex mirror is gone, allowing for a more compact camera, better movie capabilities, and enhanced auto-focus functions, among other benefits. 

But what about for astrophotography? I reviewed the Sony a7III and Nikon Z6 mirrorless cameras here on my blog and, except for a couple of points, found them excellent for the demands of most astrophotography. 

For the last two years I’ve primarily used Canon’s astro-friendly and red-sensitive EOS Ra mirrorless, a model sadly discontinued in September 2021 after just two years on the market. I reviewed that camera in the April 2020 issue of Sky & Telescope magazine, with a quick first look here on my blog

The superb performance of the Ra has prompted me to stay with the Canon mirrorless R system for future camera purchases. Here I test the mid-priced R6, introduced in August 2020.

CLICK or TAP on an image to bring it up full screen for closer inspection. All images are © 2021 by Alan Dyer/AmazingSky.com. Use without permission is prohibited.

M31, the spiral galaxy in Andromeda, with the Canon R6 mirrorless camera. It is a stack of 8 x 8-minute exposures at ISO 800, blended with a stack of 8 x 2-minute exposures at ISO 400 for the core, to prevent it from overexposing too much, all with a SharpStar 76mm apo refractor at f/4.4 with its field flattener/reducer.

TL;DR SUMMARY

The Canon R6 has proven excellent for astrophotography, exhibiting better dynamic range and shadow recovery than most Canon DSLRs, due to the ISO invariant design of the R6 sensor. It is on par with the low-light performance of Nikon and Sony mirrorless cameras. 

The preview image is sensitive enough to allow easy framing and focusing at night. The movie mode produces usable quality up to ISO 51,200, making 4K movies of auroras possible. Canon DSLRs cannot do this. 

Marring the superb performance are annoying deficiencies in the design, and one flaw in the image quality – an amp glow – that particularly impacts deep-sky imaging.

R6 pros

The Canon R6 is superb for its:

  • Low noise, though not exceptionally so
  • ISO invariant sensor performance for good shadow recovery 
  • Sensitive live view display with ultra-high ISO boost in Movie mode 
  • Relatively low noise Movie mode with full frame 4K video
  • Low light auto focus and accurate manual focus assist  
  • Good battery life 

R6 cons

The Canon R6 is not so superb for its:

Design Deficiencies 

  • Lack of a top LCD screen
  • Bright timer display in Bulb on the rear screen
  • No battery level indication when shooting 
  • Low grade R3-style remote jack, same as on entry-level Canon DSLRs 

Image Quality Flaw

  • Magenta edge “amp glow” in long exposures 
The Canon Ra on the left with the 28-70mm f/2 RF lens and the Canon R6 on the right with the 70-200mm f/2/8 RF lens, two superb but costly zooms for the R system cameras.

CHOOSING THE R6

Canon’s first full-frame mirrorless camera, the 30-megapixel EOS R, was introduced in late 2018 to compete with Sony. As of late-2021 the main choices in a Canon DSLM for astrophotography are either the original R, the 20-megapixel R6, the 26-megapixel Rp, or the 45-megapixel R5. 

The new 24-megapixel Canon R3, while it has impressive low-noise performance, is designed primarily for high-speed sports and news photography. It is difficult to justify its $6,000 cost for astro work. 

I have not tested Canon’s entry-level, but full-frame Rp. While the Rp’s image quality is likely quite good, its small battery and short lifetime on a single charge will be limiting factors for astrophotography. 

Nor have I tested the higher-end R5. Friends who use the R5 for nightscape work love it, but with smaller pixels the R5 will be noisier than the R6, which lab tests at sites such as DPReview.com seem to confirm. 

Meanwhile, the original EOS R, while having excellent image quality and features, is surely destined for replacement in the near future – with a Canon EOS R Mark II? The R’s successor might be a great astrophoto camera, but with the Ra gone, I feel the R6 is currently the prime choice from Canon, especially for nightscapes.

I tested an R6 purchased in June 2021 and updated in August with firmware v1.4. I’ll go through its performance and functions with astrophotography in mind. I’ve ignored praised R6 features such as eye tracking autofocus, in-body image stabilization, and high speed burst rates. They are of limited or no value for astrophotography. 

Along the way, I also offer a selection of user tips, some of which are applicable to other cameras. 

LIVE VIEW FOCUSING AND FRAMING

“Back-of-the-camera” views of the R6 in its normal Live View mode (upper left) and its highly-sensitive Movie Mode (upper right), compared to views with four other cameras. Note the Milky Way visible with the R6 in its Movie mode, similar to the Sony in Bright Monitoring mode.

The first difference you will see when using any new mirrorless camera, compared to even a high-end DSLR, is how much brighter the “Live View” image is when shooting at night. DSLM cameras are always in Live View – even the eye-level viewfinder presents a digital image supplied by the sensor. 

As such, whether on the rear screen on in the viewfinder, you see an image that closely matches the photo you are about to take, because it is the image you are about to take. 

To a limit. DSLMs can do only so much to simulate what a long 30-second exposure will look like. But the R6, like many DSLMs, goes a long way in providing a preview image bright enough to frame a dark scene and focus on bright stars. Turn on Exposure Simulation to brighten the live image, and open the lens as wide as possible. 

The Canon R6 in its Movie Mode at ISO 204,800 and with a lens wide open.

But the R6 has a trick up its sleeve for framing nightscapes. Switch the Mode dial to Movie, and set the ISO up to 204,800 (or at night just dial in Auto ISO), and with the lens wide open and shutter on 1/8 second (as above), the preview image will brighten enough to show the Milky Way and dark foreground, albeit in a noisy image. But it’s just for aiming and framing.

This is similar to the excellent, but well-hidden Bright Monitoring mode on Sony Alphas. This high-ISO Movie mode makes it a pleasure using the R6 for nightscapes. The EOS R and Ra do not have this ability. While their live view screens are good, they are not as sensitive as the R6’s, with the R and Ra’s Movie modes able to go up to only ISO 12,800. The R5 can go up to “only” ISO 51,200 in its Movie mode, good but not quite high enough for live framing on dark nights. 

Comparing Manual vs. Auto Focus results with the R6.

The R6 will also autofocus down to a claimed EV -6.5, allowing it to focus in dim light for nightscapes, a feat impossible in most cameras. In practice with the Canon RF 15-35mm lens at f/2.8, I found the R6 can’t autofocus on the actual dark landscape, but it can autofocus on bright stars and planets (provided, of course, the camera is fitted with an autofocus lens). 

Autofocusing on bright stars proved very accurate. By comparison, while the Ra can autofocus on distant bright lights, it fails on bright stars or planets. 

Turning on Focus Peaking makes stars turn red, yellow or blue (your choice of colours) when they are in focus, as a reassuring confirmation. 

The Focus Peaking and Focus Guide menu.
The R6 live view display with Focus Guide arrows on and focused on a star, Antares.

In manual focus, an additional Focus Aid overlay provides arrows that close up and turn green when in focus on a bright star or planet. Or you can zoom in by 5x or 10x to focus by eye the old way by examining the star image. I wish the R6 had a 15x or 20x magnification; 5x and 10x have long been the Canon standards. Only the Ra offered 30x for ultra-precise focusing on stars. 

In all, the ease of framing and focusing will be the major improvement you’ll enjoy by moving to any mirrorless, especially if your old camera is a cropped-frame Canon Rebel or T3i! But the R6 particularly excels at ease of focusing and framing. 

NOISE PERFORMANCE

The key camera characteristic for astrophoto use is noise. I feel it is more important than resolution. There’s little point in having lots of fine detail if it is lost in a blizzard of high-ISO noise. And for astro work, we are almost always shooting at high ISOs.

Comparing the R6’s noise at increasingly higher ISO speeds on a starlit nightscape.

With just 20 megapixels, low by today’s standards, the R6 has individual pixels, or more correctly “photosites,” that are each 6.6 microns in size, the “pixel pitch.” 

By comparison, the 30-megapixel R (and Ra) has a pixel pitch of 5.4 microns, the 45-megapixel R5’s pixel pitch is 4.4 microns, while the acclaimed low-light champion in the camera world, the 12-megapixel Sony a7sIII, has large 8.5-micron photosites. 

The bigger the photosites (i.e. the larger the pixel pitch), the more photons each photosite can collect in a given amount of time – and the more photons they can collect, period, before they overfill and clip highlights. More photons equals more signal, and therefore a better signal-to-noise ratio, while the greater “full-well depth” yields higher dynamic range. 

Each generation of camera also improves the signal-to-noise ratio by suppressing noise via its sensor design and improved signal processing hardware and firmware. The R6 uses Canon’s latest DIGIC X processor shared by the company’s other mirrorless cameras. 

Comparing the R6 noise with the 6D MkII and EOS Ra on a deep-sky subject, galaxies.

In noise tests comparing the R6 against the Ra and Canon 6D Mark II, all three cameras showed a similar level of noise at ISO settings from 400 up to 12,800. But the 6D Mark II performed well only when properly exposed. Both the R6 and Ra performed much better for shadow recovery in underexposed scenes. 

Comparing the R6 noise with with the 6D MkII and EOS Ra on a shadowed nightscape.
Comparing the R6 noise with the EOS Ra on the Andromeda Galaxy at typical deep-sky ISO speeds.

In nightscapes and deep-sky images the R6 and Ra looked nearly identical at each of their ISO settings. This was surprising considering the Ra’s smaller photosites, which perhaps attests to the low noise of the astronomical “a” model. 

Or it could be that the R6 isn’t as low noise as it should be for a 20 megapixel camera. But it is as good as it gets for Canon cameras, and that’s very good indeed.

I saw no “magic ISO” setting where the R6 performed better than at other settings. Noise increased in proportion to the ISO speed. It proved perfectly usable up to ISO 6400, with ISO 12,800 acceptable for stills when necessary. 

ISO INVARIANCY

The flaw in many Canon DSLRs, one documented in my 2017 review of the 6D Mark II, was their poor dynamic range due to the lack of an ISO invariant sensor design. 

The R6, as with Canon’s other R-series cameras, has largely addressed this weakness. The sensor in the R6 appears to be nicely ISO invariant and performs as well as the Sony and Nikon cameras I have used and tested, models praised for their ISO invariant behaviour. 

Where this trait shows itself to advantage is on nightscapes where the starlit foreground is often dark and underexposed. Bringing out detail in the shadows in raw files requires a lot of Shadow Recovery or increasing the Exposure slider. Images from an ISO invariant sensor can withstand the brightening “in post” far better, with minimal noise increase or degradations such as a loss of contrast, added banding, or horrible discolourations. 

Comparing the R6 for ISO Invariancy on a starlit nightscape.

To test the R6, I shot sets of images at the same shutter speed, one well-exposed at a high ISO, then several at successively lower ISOs to underexpose by 1 to 5 stops. I then brightened the underexposed images by increasing the Exposure in Camera Raw by the same 1 to 5 stops. In an ideal ISO invariant sensor, all the images should look the same. 

The R6 did very well in images underexposed by up to 4 stops. Images underexposed by 5 stops started to fall apart, but I’ve seen that in Sony and Nikon images as well. 

Comparing the R6 for ISO Invariancy on a moonlit nightscape.

This behaviour applies to images underexposed by using lower ISOs than what a “normal” exposure might require. Underexposing with lower ISOs can help maintain dynamic range and avoid highlight clipping. But with nightscapes, foregrounds can often be too dark even when shot at an ISO high enough to be suitable for the sky. Foregrounds are almost always underexposed, so good shadow recovery is essential for nightscapes, and especially time-lapses, when blending in separate longer exposures for the ground is not practical.

With its improved ISO invariant sensor, the R6 will be a fine camera for nightscape and time-lapse use, which was not true of the 6D Mark II. 

For those interested in more technical tests and charts, I refer you to DxOMark’s report on the Canon R6.  

Comparing R6 images underexposed in 1-stop increments by using shorter shutter speeds.
Comparing R6 images underexposed in 1-stop increments by using smaller apertures.

However, to be clear, ISO invariant behaviour doesn’t help you as much if you underexpose by using too short a shutter speed or too small a lens aperture. I tested the R6 in series of images underexposed by keeping ISO the same but decreasing the shutter speed then the aperture in one-stop increments. 

The underexposed images fell apart in quality much sooner, when underexposed more than 3 stops. Again, this is behaviour similar to what I’ve seen in Sonys and Nikons. For the best image quality I feel it is always a best practice to expose well at the camera. Don’t count on saving images in post. 

An in-camera image fairly well exposed with an ETTR histogram.

TIP: Underexposing by using too short an exposure time is the major mistake astrophotographers make, who then wonder why their images are riddled with odd artifacts and patten noise. Always Expose to the Right (ETTR), even with ISO invariant cameras. The best way to avoid noise is to give your sensor more signal, by using longer exposures or wider apertures. Use settings that push the histogram to the right. 

LONG EXPOSURE NOISE REDUCTION

All cameras will exhibit thermal noise in long exposures, especially on warm nights. This form of noise peppers the shadows with hot pixels, often brightly coloured. 

This is not the same as the shot and read noise that adds graininess to high-ISO images and that noise reduction software can smooth out. This is a common misunderstanding, even among professional photographers who should know better! 

Thermal noise is more insidious and harder to eliminate in post without harming the image. However, Monika Deviat offers a clever method here at her website

The standard Canon LENR menu.

Long Exposure Noise Reduction (LENR) eliminates this thermal noise by taking a “dark frame” and subtracting it in-camera to yield a raw file free of hot pixels. 

And yes, LENR does apply to raw files, another fact even many professional photographers don’t realize. It is High ISO Noise Reduction that applies only to JPGs, along with Color Space and Picture Styles.

Comparing a dark nightscape without and with LENR on a warm night. Hot pixels are mostly gone at right.

The LENR option on the R6 did eliminate most hot pixels, though sometimes still left, or added, a few. LENR is needed more on warm nights, and with longer exposures at higher ISOs. So the extent of thermal noise in any camera can vary a lot from shoot to shoot.

When LENR is active, the R6’s rear screen lights up with “Busy,” which is annoyingly bright. To hide this display, the only option is to close the screen. 

As with the EOS Ra, and all mirrorless cameras, the R6 has no “dark frame buffer” that allows several exposures to be taken in quick succession even with LENR on. Canon’s full-frame DSLRs have this little-known buffer that allows 3, 4, or 5 “light frames” to be taken in a row before the LENR dark frame kicks in a locks up the camera on Busy. 

Comparing long exposure images with the lens cap on (dark frames), to show just thermal noise. The right edge of the frame is shown, blown up, to reveal the amp glow, which LENR removes.

With all Canon R cameras, and most other DSLRs, turning on LENR forces the camera to take a dark frame after every light frame, doubling the time it takes to finish every exposure. That’s a price many photographers aren’t willing to pay, but on warm nights it can be necessary, and a best practice, for the reward of cleaner images.

The standard Canon Sensor Cleaning menu.

TIP: If you find hot pixels are becoming more obvious over time, try this trick: turn on the Clean Manually routine for 30 seconds to a minute. In some cameras this can remap the hot pixels so the camera can better eliminate them.  

STAR QUALITY 

Using LENR with the R6 did not introduce any oddities such as oddly-coloured, green or wiped-out stars. Even without LENR I saw no evidence of green stars, a flaw that plagues some Sony cameras at all times, or Nikons when using LENR. 

Comparing the R6 for noise and star colours at typical deep-sky ISOs and exposure times.

Canons have always been known for their good star colours, and the R6 is no exception. According to DPReview the R6 has a low-pass anti-alias filter in front of its sensor. Cameras which lack such a sensor filter do produce sharper images, but stars that occupy only one or two pixels might not de-Bayer properly into the correct colours. That’s not an issue with the R6.

I also saw no “star-eating,” a flaw Nikons and Sonys have been accused of over the years, due to aggressive in-camera noise reduction even on raw files. Canons have always escaped charges of star-eating. 

VIGNETTING/SHADOWING

DSLRs are prone to vignetting along the top and bottom of the frame from shadowing by the upraised mirror and mirror box. Not having a mirror, and a sensor not deeply recessed in the body, largely eliminates this edge vignetting in mirrorless cameras. 

This illustrates the lack of edge shadows but magenta edge glows in a single Raw file boosted for contrast.

That is certainly true of the R6. Images boosted a lot in contrast, as we do with deep-sky photos, show not the slightest trace of vignetting along the top or bottom edges There were no odd clips or metal bits intruding into the light path, unlike in the Sony a7III I tested in 2018. 

The full frame of the R6 can be used without need for cropping or ad hoc edge brightening in post. Except …

EDGE ARTIFACTS/AMP GLOWS

The R6 did exhibit one serious and annoying flaw in long exposure images – a magenta glow along the edges, especially the right edge and lower right corner. 

Comparing a close-up of a nightscape, without and with LENR, to show the edge glow gone with LENR on.

Whether this is the true cause or not, it looks like “amplifier glow,” an effect caused by heat from circuitry illuminating the sensor with infra-red light. It shows itself when images are boosted in contrast and brightness in processing. It’s the sort of flaw revealed only when testing for the demands of astrophotography. It was present in images I took through a telescope, so it is not IR leakage from an auto-focus lens. 

I saw this type of amp glow with the Sony a7III, a flaw eventually eliminated in a firmware update that, I presume, turned off unneeded electronics in long exposures. 

Amp glow is something I have not seen in Canon cameras for many years. In a premium camera like the R6 it should not be there. Period. Canon needs to fix this with a firmware update.

It is the R6’s only serious image flaw, but it’s surprising to see it at all. Turning on LENR eliminates the amp glow, as it should, but using LENR is not always practical, such as in time-lapses and star trails.

For deep-sky photography images are pushed to extremes of contrast, revealing any non-uniform illumination or colour. The usual practice of taking and applying calibration dark frames should also eliminate the amp glow. But I’d rather it not be there in the first place!

RED SENSITIVITY

The R6 I bought was a stock “off-the-shelf” model. It is Canon’s now-discontinued EOS Ra model that is (or was) “filter-modified” to record a greater level of the deep red wavelength from red nebulas in the Milky Way. Compared to the Ra, the R6 did well, but could not record the depth of nebulosity the Ra can, to be expected for a stock camera. 

Comparing the stock R6 with the filter-modified Ra on Cygnus nebulosity.

In wide-field images of the Milky Way, the R6 picked up a respectable level of red nebulosity, especially when shooting through a broadband light pollution reduction filter, and with careful processing. 

Comparing the stock R6 with the filter-modified Ra on the Swan Nebula with a telescope with minimal processing to the Raw images.
Comparing the stock R6 with the filter-modified Ra on the Swan Nebula with a telescope with a dual narrowband filter and with colour correction applied to the single Raw images.

However, when going after faint nebulas through a telescope, even the use of a narrowband filter did not help bring out the target. Indeed, attempting to correct the extreme colour shift introduced by such a filter resulted in a muddy mess and accentuated edge glows with the R6, but worked well with the Ra. 

While the R6 could be modified by a third party, the edge amp glow might spoil images, as a filter modification can make a sensor even more sensitive to IR light, potentially flooding the image with unwanted glows. 

TIP: Buying a used Canon Ra (if you can find one) might be one choice for a filter-modified mirrorless camera, one much cheaper than a full frame cooled CMOS camera such as a ZWO ASI2400MC. Or Spencer’s Camera sells modified versions of all the R series cameras with a choice of sensor filters. But I have not used any of their modded cameras.

RESOLUTION 

A concern of prospective buyers is whether the R6’s relatively low 20-megapixel sensor will be sharp enough for their purposes. R6 images are 5472 by 3648 pixels, much less than the 8000+ pixel-wide images from high-resolution cameras like the Canon R5, Nikon Z7II or Sony a1.

Unless you sell your astrophotos as very large prints, I’d say don’t worry. In comparisons with the 30-megapixel Ra I found it difficult to see a difference in resolution between the two cameras. Stars were nearly as well resolved in the R6, and only under the highest pixel-peeping magnification did stars look a bit more pixelated in the R6 than in the Ra. Faint stars were equally well recorded. 

Comparing resolution of the R6 vs. Ra with a blow-up of wide-field 85mm images
Comparing resolution of the R6 vs. Ra on blow-ups of the Andromeda Galaxy with a 76mm apo refractor. The R6 is more pixellated but it takes pixel peeping to see it!

The difference between 20 and 30 megapixels is not as great as you might think for arc-second-per-pixel plate scale. I think it would take going to the R5 with its 45 megapixel sensor to provide enough of a difference in resolution over the R6 to be obvious in nightscape scenes, or when shooting small, detailed deep-sky subjects such as globular clusters. 

If landscape or wildlife photography by day is your passion, with astrophotography a secondary purpose, then the more costly but highly regarded R5 might be the better choice. 

Super Resolution menu in Adobe Lightroom.

TIP: Adobe now offers (in Lightroom and in Camera Raw) a Super Resolution option, that users might think (judging by the rave reviews on-line) would be the answer to adding resolution to astro images from “low-res” cameras like the R6. 

Comparing a normal R6 image with the same image upscaled with Super Resolution.

Sorry! In my tests on astrophotos I’ve found Super Resolution results unsatisfactory. Yes, stars were less pixelated, but they became oddly coloured in the AI-driven up-scaling. Green stars appeared! The sky background also became mottled and uneven. 

I would not count on such “smart upscaling” options to add more pixels to astro-images from the R6. Then again, I don’t think there’s a need to. 

RAW vs. cRAW

Canon now offers the option of shooting either RAW or cRAW files, the latter being the same megapixel count but compressed in file size by almost a factor of two. This allows shooting twice as many images before card space runs out, perhaps useful for shooting lots of time-lapses on extended trips away from a computer. 

The R6 Image Quality menu with the cRAW Option.
Comparing an R6 cRAW with a RAW image.

However, the compression is not lossless. In high-ISO test images purposely underexposed, then brightened in post, I could see a slight degradation in cRAW images – the noise background looked less uniform and exhibited a blocky look, like JPG artifacts. 

The R6’s dual SD card slots.

TIP: With two SD card slots in the R6 (the second card can be set to record either a backup of images on card one, or serve as an overflow card) and the economy of large SD cards, there’s not the need to conserve card space as there once was. I would suggest always shooting in the full RAW format. Why accept any compression and loss of image quality? 

BATTERY LIFE

The R6 uses a new version of Canon’s standard LP-E6 battery, the LP-E6NH, that supports charging through the USB-C port and has a higher 2130mAh capacity than the 1800mAh LP-E6 batteries. However, the R6 is compatible with older batteries.

On warm nights, I found the R6 ran fine on one battery for the 3 to 4 hours needed to shoot a time-lapse sequence, with power to spare. However, as noted below, the lack of a top LCD screen means there’s no ongoing display of battery level, a deficiency for time-lapse and deep-sky work. 

For demanding applications, especially in winter, the R6 can be powered by an outboard USB power bank that has “Power Delivery” capability. That’s a handy feature. There’s no need to install a dummy battery leading out to a specialized power source. 

The R6’s Connection menu with Airplane mode to turn off battery-eating WiFi and Bluetooth.

TIP: Putting the camera into Airplane mode (to turn off WiFi and Bluetooth), turning off the viewfinder, and either switching off or closing the rear screen all helps conserve power. The R6 does not have GPS built in. Tagging images with location data requires connecting to your phone.

VIDEO USE

A major selling point for me was the R6’s low-light video capability. It replaces my Sony A7III, which had been my “go to” camera for real-time 4K movies of auroras. 

As best I can tell (from the dimmer auroras I’ve shot to date), the R6 performs equally as well as the Sony. It is able to record good quality (i.e. acceptably noise-free) 4K movies at ISO 25,600 to ISO 51,200. While it can shoot at up to ISO 204,800, the excessive noise makes the top ISO an emergency-use only setting. 

The R6’s Movie size and quality options, with 4K and Full HD formats and frame rates.
Comparing the R6 on a dim aurora at various high ISO speeds. Narrated at the camera — excuse the wind noise! Switch to HD mode for the best video playback quality. This was shot in 4K but WordPress plays back only in HD.

The R6 can shoot at a dragged shutter speed as slow as 1/8-second – good, though not as slow as the Sony’s 1/4-second slowest shutter speed in movie mode. That 1/8-second shutter speed and a fast f/1.4 to f/2 lens are the keys to shooting movies of the night sky. Only when auroras get shadow-casting bright can we shoot at the normal 1/30-second shutter speed and at lower ISOs.

As with Nikons (but not Sonys), the Canon R6 saves its movie settings separately from its still settings. When switching to Movie mode you don’t have to re-adjust the ISO, for example, to set it higher than it might have been for stills, very handy for taking both stills and movies of an active aurora, where quick switching is often required. 

Unlike the R and Rp, the R6 captures 4K movies from the full width of the sensor, preserving the field of view of wide-angle lenses. This is excellent for aurora shooting. 

The R6’s Movie Cropping menu option
A 4K movie of the Moon in full-frame and copped-frame modes, narrated at the camera. Again, this was shot in 4K but WordPress plays back only in HD.
Comparing blow-ups of frame-grabbed stills from a full-frame 4K vs. Cropped frame 4K. The latter is less pixellated.

However, the R6 offers the option of a “Movie Crop” mode. Rather than taking the 4K movie downsampled from the entire sensor, this crop mode records from a central 1:1 sampled area of the sensor. That mode can be useful for high-magnification lunar and planetary imaging, for ensuring no loss of resolution. It worked well, producing videos with less pixelated fine details in test movies of the Moon. 

Though of course I have yet to test it on one, the R6 should be excellent for movies of total solar eclipses. It can shoot 4K up to 60 frames per second in both full frame and cropped frame. It cannot shoot 6K (buy the R3!) or 8K (buy the R5!). 

The R6’s Canon Log settings menu for video files.

Shooting in the R6’s Canon cLog3 profile records internally in 10-bit, preserving more dynamic range in movies, up to 12 stops. During eclipses, that will be a benefit for recording totality, with the vast range of brightness in the Sun’s corona. It should also aid in shooting auroras which can vary over a huge range in brightness. 

Grading a cLog format movie in Final Cut under Camera LUT.

TIP: Processing cLog movies, which look flat out of camera, requires applying a cLog3 Look Up Table, or LUT, to the movie clips in editing, a step called “colour grading.” This is available from Canon, from third-party vendors or, as it was with my copy of Final Cut Pro, might be already installed in your video editing software. When shooting, turn on View Assist so the preview looks close to what the final graded movie will look like.

EXPOSURE TRACKING IN TIME-LAPSES

In one test, I shot a time-lapse from twilight to darkness with the R6 in Aperture Priority auto-exposure mode, of a fading display of noctilucent clouds. I just let the camera lengthen the shutter speed on its own. It tracked the darkening sky very well, right down to the camera’s maximum exposure time of 30 seconds, using a fish-eye lens at f/2.8. This demonstrated that the light meter in the R6 was sensitive enough to work well in dim light.

Other cameras I have used cannot do this. The meter fails at some point and the exposure stalls at 5 or 6 seconds long, resulting in most frames after that being underexposed. By contrast, the R6 showed excellent performance, negating the need for special bulb ramping intervalometers for some “holy grail” scenes. Here’s the resulting movie.

A time-lapse of 450 frames from 0.4 seconds to 30 seconds, with the R6 in Av mode. Set to 1080P for the best view!
A screenshot from LRTimelapse showing the smoothness of the exposure tracking (the blue line) through the sequence,

In addition, the R6’s exposure meter tracked the darkening sky superbly, with nary a flicker or variation. Again, few cameras can do this. Nikons have an Exposure Smoothing option in their Interval Timers which works well.

The R6 has no such option but doesn’t seem to need it. The exposure did fail at the very end, when the shutter reached its maximum of 30 seconds. If I had the camera on Auto ISO, it might have started to ramp up the ISO to compensate, a test I have yet to try. Even so, this is impressive time-lapse performance in auto-exposure.

MISSING FEATURES

The R6, like the low-end Rp, lacks a top LCD screen for display of camera settings and battery level. In its place we get a traditional Mode dial, which some daytime photographers will prefer. But for astrophotography, a backlit top LCD screen provides useful information during long exposures. 

The R6 top and back of camera view.

Without it, the R6 provides no indication of battery level while a shoot is in progress, for example, during a time-lapse. A top screen is also useful for checking ISO and other settings by looking down at the camera, as is usually the case when it’s on a tripod or telescope. 

The lack of a top screen is an inconvenience for astrophotography. We are forced to rely on looking at the brighter rear screen for all information. It is a flip-out screen, so can be angled up for convenient viewing on a telescope.

The R6’s flip screen, similar to most other new Canon cameras.

The R6 has a remote shutter port for an external intervalometer, or control via a time-lapse motion controller. That’s good! 

However, the port is Canon’s low-grade 2.5mm jack. It works, and is a standard connector, but is not as sturdy as the three-pronged N3-style jack used on Canon’s 5D and 6D DSLRs, and on the R3 and R5. Considering the cost of the R6, I would have expected a better, more durable port. The On/Off switch also seems a bit flimsy and easily breakable under hard use. 

The R6’s side ports, including the remote shutter/intervalometer port.

These deficiencies provide the impression of Canon unnecessarily “cheaping out” on the R6. You can forgive them with the Rp, but not with a semi-professional camera like the R6.

INTERVAL TIMER

Unlike the Canon R and Ra (which still mysteriously lack a built-in interval timer, despite firmware updates), the R6 has one in its firmware. Hurray! This can be used to set up a time-lapse sequence, but on exposures only up to the maximum of 30 seconds allowed by the camera’s shutter speed settings, true of most in-camera intervalometers. 

The Interval Timer menu page.

For 30-second exposures taken in succession as quickly as possible the interval on the R6 has to be set to 34 seconds. The reason is that the 30-second exposure is actually 32 seconds, true of all cameras. With the R6, having a minimum gap in time between shots requires an Interval not of 33 seconds as with some cameras, but 34 seconds. Until you realize this, setting the intervalometer correctly can be confusing. 

Like all Canon cameras, the R6 can be set to take only up to 99 frames, not 999. That seems a dumb deficiency. Almost all time-lapse sequences require at least 200 to 300 frames. What could it possibly take in the firmware to add an extra digit to the menu box? It’s there at in the Time-lapse Movie function that assembles a movie in camera, but not here where the camera shoots and saves individual frames. It’s another example where you just can’t fathom Canon’s software decisions.

Setting the Interval Timer for rapid sequence shots with a 30-second exposure.

TIP: If you want to shoot 100 or more frames, set the Number of Frames to 00, so it will shoot until you tell the camera to stop. But awkwardly, Canon says the way to stop an interval shoot is to turn off the camera! That’s crude, as doing so can force you to refocus if you are using a Canon RF lens. Switching the Mode dial to Bulb will stop an interval shoot, an undocumented feature. 

BULB TIMER

As with most recent Canon DSLRs and DSLMs, the menu also includes a Bulb Timer. This allows setting an exposure of any length (many minutes or hours) when the camera is in Bulb mode. This is handy for single long shots at night. 

The Bulb Timer menu page. Bulb Timer only becomes an active choice when the camera is on Bulb.

However, it cannot be used in conjunction with the Interval Timer to program a series of multi-minute exposures, a pity. Instead, a separate outboard intervalometer has to be used for taking an automatic set of any exposures longer than 30 seconds, true of all Canons. 

In Bulb and Bulb Timer mode, the R6’s rear screen lights up with a bright Timer readout. While the information is useful, the display is too bright at night and cannot be dimmed, nor turned red for night use, exactly when you are likely to use Bulb. The power-saving Eco mode has no effect on this display, precisely when you would want it to dim or turn off displays to prolong battery life, another odd deficiency in Canon’s firmware. 

The Bulb Timer screen active during a Bulb exposure. At night it is bright!

The Timer display can only be turned off by closing the flip-out screen, but now the viewfinder activates with the same display. Either way, a display is on draining power during long exposures. And the Timer readout lacks any indication of battery level, a vital piece of information during long shoots. The Canon R, R3 and R5, with their top LCD screens, do not have this annoying “feature.” 

TIP: End a Bulb Timer shoot prematurely by hitting the Shutter button. That feature is documented. 

IN-CAMERA IMAGE STACKING

The R6 offers a menu option present on many recent Canon cameras: Multiple Exposure. The camera can take and internally stack up to 9 images, stacking them by using either Average (best for reducing noise) or Bright mode (best for star trails). An Additive mode also works for star trails, but stacking 9 images requires reducing the exposure of each image by 3 stops, say from ISO 1600 to ISO 200, as I did in the example below. 

The Multiple Exposure menu page.

The result of the internal stacking is a raw file, with the option of also saving the component raws. While the options work very well, in all the cameras I’ve owned that offer such functions, I’ve never used them. I prefer to do any stacking needed later at the computer. 

Comparing a single image with a stack of 9 exposures with 3 in-camera stacking methods.

TIP: The in-camera image stacking options are good for beginners wanting to get advanced stacking results with a minimum of processing fuss later. Use Average to stack ground images for smoother noise. Use Bright for stacking sky images for star trails. Activate one of those modes, then control the camera with a separate intervalometer to automatically shoot and internally stack several multi-minute exposures. 

SHUTTER OPERATION

Being a mirrorless camera, there is no reflex mirror to introduce vibration, and so no need for a mirror lockup function. The shutter can operate purely mechanically, with physical metal curtains opening and closing to start and end the exposure. 

However, the default “out of the box” setting is Electronic First Curtain, where the actual exposure, even when on Bulb, is initiated electronically, but ended by the mechanical shutter. That’s good for reducing vibration, perhaps when shooting the Moon or planets through a telescope at high magnification. 

R6 Shutter Mode options.

In Mechanical, the physical curtains both start and end the exposure. It’s the mode I usually prefer, as I like to hear the reassuring click of the shutter opening. I’ve never found shutter vibration a problem when shooting deep sky images on a telescope mount of any quality. 

In Mechanical mode the shutter can fire at up to 12 frames a second, or up to 20 frames a second in Electronic mode where both the start and end of the exposure happen without the mechanical shutter. That makes for very quiet operation, good for weddings and golf tournaments! 

Electronic Shutter Mode is for fastest burst rates but has limitations.

Being vibration free, Electronic shutter might be great during total solar eclipses for rapid-fire bursts at second and third contacts when shooting through telescopes. Maximum exposure time is 1/2 second in this mode, more than long enough for capturing fleeting diamond rings.

Longer exposures needed for the corona will require Mechanical or Electronic First Curtain shutter. Combinations of shutter modes, drive rates (single or continuous), and exposure bracketing can all be programmed into the three Custom Function settings (C1, C2 and C3) on the Mode dial, for quick switching at an eclipse. It might not be until April 8, 2024 until I have a chance to test these features. And by then the R6 Mark II will be out! 

TIP: While the R6’s manual doesn’t state it, some reviews mention (including at DPReview) that when the shutter is in fully Electronic mode the R6’s image quality drops from 14-bit to 12-bit, true of most other mirrorless cameras. This reduces dynamic range. I would suggest not using Electronic shutter for most astrophotography, even for exposures under 1/2 second. For longer exposures, it’s a moot point as it cannot be used. 

The menu option that fouls up all astrophotographers using an R-series camera.

TIP: The R6 has the same odd menu item that befuddles many a new R-series owner, found on Camera Settings: Page 4. “Release Shutter w/o Lens” defaults to OFF, which means the camera will not work if it is attached to a manual lens or telescope it cannot connect to electronically. Turn it ON and all will be solved. This is a troublesome menu option that Canon should eliminate or default to ON. 

OTHER MENU FEATURES

The rear screen is fully touch sensitive, allowing all settings to be changed on-screen if desired, as well as by scrolling with the joystick and scroll wheels. I find going back to an older camera without a touchscreen annoying – I keep tapping the screen expecting it to do something! 

The Multi-Function Button brings up an array of 5 settings to adjust. This is ISO.

The little Multi-Function (M-Fn) button is a worth getting used to, as it allows quick access to a choice of five important functions such as ISO, drive mode and exposure compensation. However, the ISO, aperture and shutter speed are all changeable by the three scroll wheels. 

The Q button brings up the Quick Menu for displaying and adjusting key functions.

There’s also the Quick menu activated by the Q button. While the content of the Quick menu screen can’t be edited, it does contain a good array of useful functions, adjustable with a few taps. 

Under Custom settings, the Dials and Buttons can be re-assigned to other functions.

Unlike Sonys, the R6 has no dedicated Custom buttons per se. However, it does offer a good degree of customization of its buttons, by allowing users to re-assign them to other functions they might find more useful than the defaults. For example ….

This shows the AF Point button being re-assigned to the Maximize Screen Brightness (Temporary) command.
  • I’ve taken the AF Point button and assigned it to the Maximize Screen Brightness function, to temporarily boost the rear screen to full brightness for ease of framing. 
  • The AE Lock button I assigned to switch the Focus Peaking indicators on and off, to aid manual focusing when needed. 
  • The Depth of Field Preview button I assigned to switching between the rear screen and viewfinder, through that switch does happen automatically as you put your eye to the viewfinder.
  • The Set button I assigned to turning off the Rear Display, though that doesn’t have any effect when the Bulb Timer readout is running, a nuisance. 

While the physical buttons are not illuminated, having a touch screen makes it less necessary to access buttons in the dark. It’s a pity the conveniently positioned but mostly unused Rate button can’t be re-programmed to more useful functions. It’s a waste of a button. 

Set up the Screen Info as you like it by turning on and off screen pages and deciding what each should show.

TIP: The shooting screens, accessed by the Info button (one you do need to find in the dark!), can be customized to show a little, a lot, or no information, as you prefer. Take the time to set them up to show just the information you need over a minimum of screen pages. 

LENS AND FILTER COMPATIBILITY

The new wider RF mount accepts only Canon and third-party RF lenses. However, all Canon and third-party EF mount lenses (those made for DSLRs) will fit on RF-mount bodies with the aid of the $100 Canon EF-to-RF lens adapter. 

The Canon ER-to-RF lens adapter will be needed to attach R cameras to most telescope camera adapters and Canon T-rings made for older DSLR cameras.

This adapter will be necessary to attach any Canon R camera to a telescope equipped with a standard Canon T-ring. That’s especially true for telescopes with field flatterers where maintaining the standard 55mm distance between the flattener and sensor is critical for optimum optical performance. 

The shallower “flange distance” between lens and sensor in all mirrorless cameras means an additional adapter is needed not just for the mechanical connection to the new style of lens mount, but also for the correct scope-to-sensor spacing. 

The extra spacing provided by a mirrorless camera has the benefit of allowing a filter drawer to be inserted into the light path. Canon offers a $300 lens adapter with slide-in filters, though the choice of filters useful for astronomy that fit Canon’s adapter is limited. AstroHutech offers a few IDAS nebula filters.

Clip-in filters made for the EOS R, such as those offered by Astronomik, will also fit the R6. Though, again, most narrowband filters will not work well with an unmodified camera.

The AstroHutech adapter allows inserting filters into the light path on telescopes.

TIP: Alternatively, AstroHutech also offers its own lens adapter/filter drawer that goes from a Canon EF mount to the RF mount, and accepts standard 52mm or 48mm filters. It is a great way to add interchangeable filters to any telescope when using an R-series camera, while maintaining the correct back-focus spacing. I use an AstroHutech drawer with my Ra, where the modified camera works very well with narrowband filters. Using such filters with a stock R6 won’t be as worthwhile, as I showed above. 

A trio of Canon RF zooms — all superb but quite costly.

As of this writing, the selection of third-party lenses for the Canon RF mount is limited, as neither Canon or Nikon have “opened up” their system to other lens makers, unlike Sony with their E-mount system. For example, we have yet to see much-anticipated RF-mount lenses from Sigma, Tamron and Tokina. 

A trio of third party RF lenses — L to R: the TTArtisan 7.5mm f/2 and 11mm f/2.8 fish-eyes and the Samyang/Rokinon AF 85mm f/1.4.

Samyang offers 14mm and 85mm auto-focus RF lenses, but now only under their Rokinon branding. I tested the Samyang RF 85mm f/1.4 here at AstroGearToday

The few third-party lenses that are available, from TTArtisan, Venus Optics and other boutique Chinese lens companies, are usually manual focus lenses with reverse-engineered RF mounts offering no electrical contact with the camera. Some of these wide-angle lenses are quite good and affordable. (I tested the TTArtisan 11mm fish-eye here.)

Until other lens makers are “allowed in,” if you want lenses with auto-focus and camera metadata connections, you almost have to buy Canon. Their RF lenses are superb, surpassing the quality of their older EF-mount equivalents. But they are costly. I sold off a lot of my older lenses and cameras to help pay for the new Canon glass! 

I also have reviews of the superb Canon RF 15-35mm f/2.8, as well as the unique Canon RF 28-70mm f/2 and popular Canon RF 70-200mm f/2.8 lenses (a trio making up the  “holy trinity” of zooms) at AstroGearToday.com.

CONTROL COMPATIBILITY 

Astrophotographers often like to operate their cameras at the telescope using computers running specialized control software. I tested the R6 with two popular Windows programs for controlling DSLR and now mirrorless cameras, BackyardEOS (v3.2.2) and AstroPhotographyTool (v3.88). Both recognized and connected to the R6 via its USB port. 

Both programs recognized the Canon R6.

Another popular option is the ASIair WiFi controller from ZWO. It controls cameras via one of the ASIair’s USB ports, and not (confusingly) through the Air’s remote shutter jack marked DSLR. Under version 1.7 of its mobile app, the ASIair now controls Canon R cameras and connected to the R6 just fine, allowing images to be saved both to the camera and to the Air’s own MicroSD card. 

With an update in 2021, the ZWO ASIair now operates Canon R-series cameras.

The ASIair is an excellent solution for both camera control and autoguiding, with operation via a mobile device that is easier to use and power in the field than a laptop. I’ve not tried other hardware and software controllers with the R6. 

TIP: While the R6, like many Canon cameras, can be controlled remotely with a smartphone via the CanonConnect mobile app, the connection process is complex and the connection can be unreliable. The Canon app offers no redeeming features for astrophotography, and maintaining the connection via WiFi or Bluetooth consumes battery power. 

A dim red and green aurora from Dinosaur Provincial Park, Alberta, on August 29/30, 2021. This is a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all 30 seconds at f/2.8 with the Canon 15-35mm RF lens at 25mm and the Canon R6 at ISO 4000.

SUGGESTIONS TO CANON

To summarize, in firmware updates, Canon should:

  • Fix the low-level amp glow. No camera should have amp glow. 
  • Allow either dimming the Timer readout, turning it red, or just turning it off!
  • Add a battery display to the Timer readout. 
  • Expand the Interval Timer to allow up to 999 frames, as in the Time-Lapse Movie. 
  • Allow the Rate button to be re-assigned to more functions.
  • Default the Release Shutter w/o Lens function to ON.
  • Revise the manual to correctly describe how to stop an Interval Timer shoot.
  • Allow programming multiple long exposures by combining Interval and Bulb Timer, or by expanding the shutter speed range to longer than 30 seconds, as some Nikons can do.
The Zodiacal Light in the dawn sky, September 14, 2021, from home in Alberta, with the winter sky rising. This is a stack of 4 x 30-second exposures for the ground to smooth noise, and a single 30-second exposure for the sky, all with the TTArtisan 7.5mm fish-eye lens at f/2 and on the Canon R6 at ISO 1600.

CONCLUSION

The extended red sensitivity of the Canon EOS Ra makes it better suited for deep-sky imaging. But with it now out of production (Canon traditionally never kept its astronomical “a” cameras in production for more than two years), I think the R6 is now Canon’s best camera (mirrorless or DSLR) for all types of astrophotography, both stills and movies. 

However, I cannot say how well it will work when filter-modified by a third-party. But such a modification is necessary only for recording red nebulas in the Milky Way. It is not needed for other celestial targets and forms of astrophotography. 

A composite showing about three dozen Perseid meteors accumulated over 3 hours of time, compressed into one image showing the radiant point of the meteor shower in Perseus. All frames were with the Canon R6 at ISO 6400 and with the TTArtisan 11mm fish-eye lens at f/2.8.

The low noise and ISO invariant sensor of the R6 makes it superb for nightscapes, apart from the nagging amp glow. That glow will also add an annoying edge gradient to deep-sky images, best dealt with when shooting by the use of LENR or dark frames. 

As the image of the Andromeda Galaxy, M31, at the top of the blog attests, with careful processing it is certainly possible to get fine deep-sky images with the R6. 

For low-light movies the R6 is Canon’s answer to the Sony alphas. No other Canon camera can do night sky movies as well as the R6. For me, it was the prime feature that made the R6 the camera of choice to complement the Ra. 

Alan, September 22, 2021 / © 2021 Alan Dyer / AmazingSky.com  

How to Shoot “Deep-Sky with Your DSLR”


KSPage-Feb7We’ve embarked upon a new project to produce a comprehensive tutorial on deep-sky imaging with DSLR cameras.

This past week we launched a new KickStarter campaign to fund the production of a new multi-hour video course on how to capture deep-sky objects using entry-level telescope gear and DSLR cameras.

The emphasis in the course will be on techniques for taking and processing publication-quality images as simply and easily as possible.

A Frosty Telescope Shooting Andromeda

The final video course will consist of several programs, including a video of one of our annual “Deep-Sky with Your DSLR” workshops presented locally here in Alberta. We’ve often had requests for a video version of those workshops, for those who cannot attend in person.

This is it! Here’s a short preview of some of the content.

 

We include the Workshop video, but we supplement it with much more: with video segments shot in the field by day and by night, showing how to setup and use gear, and shot in the studio showing how to process images.

Deep-Sky Photo Session in the Backyard

While much of the content has been shot and edited, there’s more to do yet. Thus our KickStarter campaign to complete the funding and production. Backers of the project through KickStarter will get the final videos at a substantial discount off the final retail price.

All the details are on the project’s KickStarter page. Click through for the listing of course content, and options for funding levels. An FAQ page answers many of the common questions.

A week into the campaign and we’re just over 50% funded, but we have a way to go yet!

M31 with Orion 80mm Apo and Celestron AVX Mount (Multiple Exposu

We hope you’ll consider backing our project, which we think will be unique on the market.

Clear skies!

— Alan, February 7, 2019 / © 2019 / AmazingSky.com 

 

 

 

Testing the Canon 6D Mark II for Deep-Sky


6D MkII on Cygnus

Following up on my earlier tests, I compare the new Canon 6D MkII camera to earlier Canon full-frame models in long, tracked exposures of the Milky Way.

A month ago I published tests of the new Canon 6D MkII camera for nightscape images, ones taken using a fixed tripod in which exposures usually have to be limited to no longer than 30 to 60 seconds, to prevent star trailing.

Despite these short exposures, we still like to extract details from the dark shadows of the scene, making nightscape images a severe test of any camera.

I refer you to my August 9, 2017 blog Testing the Canon 6D MkII for Nightscapes for the results. The 6D MkII did not fare well.

Here I test the 6D MkII for what, in many respects, is a less demanding task: shooting long exposures of deep-sky objects, the Milky Way in Cygnus in this case.

Why is this an easier task? The camera is now on a tracking mount (I used the new Sky-Watcher Star Adventurer Mini) which is polar aligned to follow the rotation of the sky. As such, exposures can now be many minutes long if needed. We can give the camera sensor as much signal as the darkness of the night sky allows. More signal equals less noise in the final images.

In addition, there are no contrasty, dark shadows where noise lurks. Indeed, the subjects of deep-sky images are often so low in contrast, as here, they require aggressive contrast boosting later in processing to make a dramatic image.

While that post-processing can bring out artifacts and camera flaws, as a rule I never see the great increase in noise, banding, and magenta casts I sometimes encounter when processing short-exposure nightscape scenes.


6D MkII at Four ISOs
The Canon 6D MkII at four typical ISO speeds in tracked exposures.

6D at Four ISOs
The original Canon 6D at four typical ISO speeds in tracked exposures.

5D MkII at Four ISOs
A Canon 5D MkII that has been filter-modified at four typical ISO speeds in tracked exposures.
For this test, I shot the same region of sky with the same 35mm lens L-Series lens at f/2.2, using three cameras:

• Canon 6D MkII (2017)

• Canon 6D (2012)

• Canon 5D MkII (2008)

Note that the 5D MkII has been “filter-modified” to make its sensor more sensitive to the deep red wavelengths emitted by hydrogen gas, the main component of the nebulas along the Milky Way. You’ll see how it picks up the red North America Nebula much better than do the two off-the-shelf “stock” cameras. (Canon had their own factory-modified “a” models in years past: the 20Da and 60Da. Canon: How about a 6D MkIIa?)

I shot at four ISO speeds typical of deep-sky images: 800, 1600, 3200, and 6400.

Exposures were 4 minutes, 2 minutes, 1 minute, and 30 seconds, respectively, to produce equally exposed frames with a histogram shifted well to the right, as it should be for a good signal-to-noise ratio.

Noisy deep-sky images with DSLR cameras are usually the result of the photographer underexposing needlessly, often in the mistaken belief that doing so will reduce noise when, in fact, it does just the opposite.

The above set of three images compares each of the three cameras at those four ISO speeds. In all cases I have applied very little processing to the images: only a lens correction, some sharpening, a slight contrast and clarity increase, and a slight color correction to neutralize the background sky.

However, I did not apply any luminance noise reduction. So all the images are noisier than what they would be in a final processed image.

Even so, all look very good. And with similar performance.

All frames were shot with Long Exposure Noise Reduction (LENR) on, for an automatic dark frame subtraction by the camera. I saw no artifacts from applying LENR vs. shots taken without it.

The 6D and 6D MkII perhaps show a little less noise than the old 5D MkII, as they should being newer cameras.

The 6D MkII also shows a little less pixelation on small stars, as it should being a 26 megapixel camera vs. 20 to 21 megapixels for the older cameras. However, you have to examine the images at pixel-peeping levels to see these differences. Nevertheless, having higher resolution without the penalty of higher noise is very welcome.


3 Canons at ISO 1600
The three cameras compared at ISO 1600. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 3200
The three cameras compared at ISO 3200. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 6400
The three cameras compared at ISO 6400. Note the histogram and region of the frame we are examining up close.
Above, I show images from the three cameras side by side at ISOs 1600, 3200, and 6400. It is tough to tell the difference in noise levels, the key characteristic for this type of astrophotography.

The new 6D MkII shows very similar levels of noise to the 6D, perhaps improving upon the older cameras a tad.

Because images are well-exposed (note the histogram at right), the 6D MkII is showing none of the flaws of its lower dynamic range reported elsewhere.

That’s the key. The 6D MkII needs a well-exposed image. Given that, it performs very well.


3 Canons Stacked & Processed
The three cameras in stacked and processed final images.
This version shows the same images but now with stacked frames and with a typical level of processing to make a more attractive and richer final image. Again, all look good, but with the modified camera showing richer nebulosity, as they do in deep-sky images.

The lead image at the very top is a final full-frame image with the Canon 6D MkII.


As such, based on my initial testing, I can recommend the Canon 6D MkII (and plan to use it myself) for deep-sky photography.

Indeed, I’ll likely have the camera filter-modified to replace my vintage yet faithful 5D MkII for most of my deep-sky shooting. The 6D MkII’s tilting LCD screen alone (a neck, back, and knee saver when attached to a telescope!) makes it a welcome upgrade from the earlier cameras.

The only drawback to the 6D MkII for deep-sky work is its limited dark frame buffer. As noted in my earlier review, it can shoot only three Raw files in rapid succession with Long Exposure Noise Reduction turned on. The 5D MkII can shoot five; the 6D can shoot four. (A 6D MkIIa should have this buffer increased to at least 4, if not 8 images.)

I make use of this undocumented feature all the time to ensure cleaner images in long deep-sky exposures, as it produces and subtracts dark frames with far greater accuracy than any taken later and applied in post-processing.


I hope you’ve found this report of interest.

With the 6D MkII so new, and between smoky skies and the interference of the Moon, I’ve had only one night under dark skies to perform these tests. But the results are promising.

For more tips on deep-sky imaging and processing see my pages on my website:

Ten Tips for Deep-Sky Images

Ten Steps to Deep-Sky Processing

Thanks and clear skies!

— Alan, September 7, 2017 / © 2017 Alan Dyer / amazingsky.com

 

Toward the Centre of the Galaxy


Toward the Centre of the Galaxy

From southern latitudes the most amazing region of the sky shines overhead late on austral autumn nights. 

There is no more spectacular part of the Milky Way than the regions around its galactic centre. Or at least in the direction of the galaxy’s core.

We can’t see the actual centre of the Galaxy, at least not with the cameras and telescopes at the disposal of amateur photographers such as myself.

It takes large observatory telescopes equipped with infrared cameras to see the stars orbiting the actual centre of the Milky Way. Doing so over many years reveals stars whipping around an invisible object with an estimated 4 million solar masses packed into the volume no larger than the solar system. It’s a black hole.

By comparison, looking in that direction with our eyes and everyday cameras, we see a mass of stars in glowing clouds intersected by lanes of dark interstellar dust.

The top image shows a wide view of the Milky Way toward the galactic centre, taking in most of Sagittarius and Scorpius and their incredible array of nebulas, star clusters and rivers of dark dust, all located in the dense spiral arms between us and the galactic core.

Starclouds and Stardust – Mosaic of the Galactic Centre
This is a mosaic of 6 segments, each segment being a stack of 4 x 3-minute exposures at f/2.8 with the 135mm Canon L-Series

Zooming into that scene reveals a panoramic close-up of the Milky Way around the galactic centre, from the Eagle Nebula in Serpens, at left, to the Cat’s Paw Nebula in Scorpius, at right.

This is the richest hunting ground for stargazers looking for deep-sky wonders. It’s all here, with field after field of telescopic and binocular sights in an area of sky just a few binocular fields wide.

The actual galactic core area is just right of the centre of the frame, above the bright Sagittarius StarCloud.

Centre of the Galaxy Area
This is a stack of 5 x 5 minute exposures with the Borg 77mm f/4 astrograph and filter-modified Canon 5D MkII at ISO 1600, taken from Tibuc Cottage near Coonabarabran, NSW, Australia.

Zooming in again shows just that region of sky in an even closer view. The contrast between the bright star fields at left and the dark intervening dust at right is striking even in binoculars – perhaps especially in binoculars.

The visual impression is of looking into dark canyons of space plunging off bright plateaus of stars.

In fact, it is just the opposite. The dark areas are created by dust much closer to us, hiding more distant stars. It is where the stars are most abundant, in the dust-free starclouds, that we see farthest into the galaxy.

In the image above the galactic centre is at right, just above the small diffuse red nebula. In that direction, some 28,000 light years away, lurks the Milky Way’s monster black hole.

Milky Way Overhead Through Trees
This is a stack of 5 x 6-minute tracked exposures with the 15mm fish-eye lens at f/4 and Canon 5D MKII at ISO 1600. The trees appear to be swirling around the South Celestial Pole at lower right above the Cottage.

To conclude my tour of the galactic centre, I back out all the way to see the entire sky and the Milky Way stretching from horizon to horizon, with the galactic centre nearly overhead in this view from 3 a.m. earlier this week.

Only from a latitude of about 30° South can you get this impressive view, what I consider one of the top “bucket-list” sights the sky has to offer.

– Alan, April 17, 2016 / © 2016 Alan Dyer / www.amazingsky.com

 

The Wonder-Filled Winter Sky


Mosaic of the Wonder-filled Winter Milky Way

The sky of December contains an amazing array of bright stars and deep-sky delights.

At this time of year we peer out toward the edge of our Galaxy, in the direction opposite to what we see in July and August. Even though we are looking away from the centre of our Galaxy, the Milky Way at this time of year contains a stunning collection of sights – for the naked eye, binoculars or a telescope.

I can’t list them all here, but most are in the lead image above! The image is a mosaic of the northern winter Milky Way, including the brilliant stars and constellations in and around Orion the Hunter.

The Milky Way extends from Perseus in the north at top, to Canis Major in the south at bottom. Throughout the scene are dark lanes and dust clouds, such as the Taurus Dark Clouds at upper right.

The Milky Way is dotted with numerous red “hydrogen-alpha” regions of emission nebulosity, such as the bright Rosette Nebula at lower left and the California Nebula at upper right. The curving arc of Barnard’s Loop surrounds the east side of Orion. Orion is below centre, with Sirius, the night sky’s brightest star, at lower left.

The constellation of Taurus is at upper right and Gemini at upper left. Auriga is at top and Perseus at upper right.

There’s an unusually bright area in Taurus just right of centre in the mosaic which I thought might be an image processing artifact. No. It’s the Gegenschein – a glow of sunlight reflected off comet dust directly opposite the Sun.

Two highlights of this sky that are great regions for binoculars are the Hyades cluster in Taurus ….

The Hyades Cluster with Aldebaran
The Hyades open star cluster in Taurus with the bright star Aldebaran, not a part of the cluster iteslf. The smaller and more distant cluster NGC 1647 is at left. This is a telephoto lens image taking in a field similar to binoculars, and is a stack of 5 x 2.5-minute exposures with the 135mm lens at f/2 and Canon 5D MkII camera at ISO 800, plus two other exposures taken through the Kenko Softon filter to add the star glows. Taken from Quailway Cottage on Dec 7, 2015 using the iOptron Sky-Tracker.

…and the Belt and Sword of Orion.

The Hyades – the face of Taurus – is one of the nearest and therefore largest open star clusters.

Orion the Hunter, who battles Taurus in the sky, contains the famous Orion Nebula, here overexposed in order to bring out the much fainter nebulosity in the region.

The magenta and blue arcs in the image below are photographic targets, but the bright Orion Nebula in Orion’s Sword is easy in binoculars, shining below the trio of his Belt Stars.

Orion Belt and Sword Mosaic
A mosaic of the Sword and Belt region of Orion the Hunter, showing the diverse array of colourful nebulas in the area, including: curving Barnard’s Loop, the Horsehead Nebula below the left star of the Belt, Alnitak, and the Orion Nebula itself as the bright region in the Sword. Also in the field are numerous faint blue reflection nebulas. The reflection nebula M78 is at top embedded in a dark nebula, and the pinkish NGC 2024 or Flame Nebula is above Alnitak. The bright orange-red star at far right is W Orionis, a type M4 long-period variable star. This is a 4-panel mosaic with each panel made of 5 x 2.5-minute exposures with the 135mm Canon L-series telephoto wide open at f/2 and the filter-modified Canon 5D MkII at ISO 1250. The night was somewhat hazy which added natural glows on the stars. No filter was employed here. The camera was on the iOptron Sky-Tracker for tracking but no guiding. Shot from outside Quailway Cottage near Portal, Arizona, Dec 7, 2015. All stacking and stitching performed in Photoshop CC 2015. Stacking done with median combine stack mode to eliminate geosat trails through the fields.

For us in the northern hemisphere, Orion and company are winter sights. But for those down under, in the southern hemisphere, this is the summer sky. So pardon the northern chauvinism in the title!

Either way, on a dark, moonless night, get out and explore the sky around Orion.

TECHNICAL:

I shot the segments for the main mosaic at top on a very clear night on December 5, 2015 from the Quailway Cottage at Portal, Arizona. This is a mosaic of 8 segments, in two columns of 4 rows, with generous overlap. Each segment was made of 4 x 2.5-minute exposures stacked with mean combine stack mode to reduce noise, plus 2 x 2.5-minute exposures taken through the Kenko Softon filter layered in with Lighten belnd mode to add the star glows. Each segment was shot at f/2.8 with the original 35mm Canon L-series lens and the filter-modified (by Hutech) Canon 5D MkII at ISO 1600, riding on the iOptron Sky-Tracker. All stacking and stitching in Photoshop CC 2015. The soft diffusion filter helps bring out the star colors in this area of sky rich in brilliant giant stars.

— Alan, December 11, 2015 / © 2015 Alan Dyer / www.amazingsky.com

Shooting the Heart Nebula


Testing the Nikon D810a

Last night I shot into the autumn Milky Way at the Heart Nebula.

I’m currently just finishing off a month of testing the new Nikon D810a camera, a special high-end DSLR aimed specifically at astrophotographers.

I’ll post a more thorough set of test shots and comparisons in a future blog, but for now here are some shots from the last couple of nights.

Above is the setup I used to shoot the image below, shot in the act of taking the image below!

The Nikon is at the focus of my much-loved TMB 92mm refractor, riding on the Astro-Physics Mach One mount. The mount is being “auto-guided” by the wonderful “just-press-one-button” SG-4 auto-guider from Santa Barbara Instruments. The scope is working at a fast f/4.4 with the help of a field flattener/reducer from Borg/AstroHutech.

I shot a set of 15 five-minute exposures at ISO 1600 and stacked, aligned and averaged them (using mean stack mode) in Photoshop. I explain the process in my workshops, but there’s also a Ten Steps page at my website with my deep-sky workflow outlined.

IC 1805 Heart Nebula (92mm D810a)
The Heart Nebula, IC 1805, in Cassiopeia, with nebula NGC 896 at upper right and star cluster NGC 1027 at left of centre. This is a stack of 15 x 5-minute exposures with the Nikon D810a as part of testing, at ISO 1600, and with the TMB 92mm apo refractor at f/4.4 with the Borg 0.85x field flattener. Taken from home Nov 29, 2015.

The main advantage of Nikon’s special “a” version of the D810 is its extended red sensitivity for a capturing just such objects in the Milky Way, nebulas which shine primarily in the deep red “H-alpha” wavelength emitted by hydrogen.

It works very well! And the D810a’s 36 megapixels really do resolve better detail, something you appreciate in wide-angle shots like this one, below, of the autumn Milky Way.

It’s taken with the equally superb 14-24mm f/2.8 Nikkor zoom lens. Normally, you would never use a zoom lens for such a demanding subject as stars, but the 14-24mm is stunning, matching or beating the performance of many “prime” lenses.

The Autumn Milky Way (Perseus to Cygnus)
The Milky Way from Perseus, at left, to Cygnus, at right, with Cassiopeia (the “W”) and Cepheus at centre. Dotted along the Milky Way are various red H-alpha regions of glowing hydrogen. The Andromeda Galaxy, M31, is at botton. The Double Cluster star cluster is left of centre. Deneb is the bright star at far right, while Mirfak, the brightest star in Perseus, is at far left. The Funnel Nebula, aka LeGentil 3, is the darkest dark nebula left of Deneb. This is a stack of 4 x 1-minute exposures at f/2.8 with the Nikkor 14-24mm lens wide open, and at 24mm, and with the Nikon D810a red-sensitive DSLR, at ISO 1600. Shot from home, with the camera on the iOptron Sky-Tracker.

The D810a’s extended red end helps reveal the nebulas along the Milky Way. The Heart Nebula, captured in the close-up at top, is just left of centre here, left of the “W” forming Cassiopeia.

The Nikon D810a is a superb camera, with low noise, high-resolution, and features of value to astrophotographers. Kudos to Nikon for serving our market!

– Alan, November 30, 2015 / © 2015 Alan Dyer / www.amazingsky.com

 

Both the Heart and Soul of Cassiopeia


Heart & Soul Nebulas (IC 1805 and IC 1848) in Cassiopeia

Here are both the heart and the soul of Cassiopeia the Queen.

Two days ago I posted an image of the Soul Nebula. Now, here is the matching Heart Nebula, in a mosaic of the glorious region of the Milky Way called the Heart and Soul Nebulas located in the constellation of Cassiopeia.

They are otherwise respectively called IC 1805 and IC 1848. Amid the swirls of nebulosity are numerous clusters of stars, such as NGC 1027 just above centre. The separate patch of nebulosity at upper right is NGC 896.

I shot the frames for this 3-segment mosaic over two nights, with one segment taken from the frames that made up the previous post. Plus I shot two others to span the region of the Milky Way that is about seven degrees long, a binocular field.

Each of the 3 segments is a stack of 12 frames, with each frame a 6-minute exposure. I used the filter-modified Canon 5D MkII and shot through the TMB 92mm apo refractor at f/4.4. All processing was in Photoshop, including the mosaic assembly.

In all, it’s the best image I’ve taken of this much-shot area of the sky. It really brings out the diversity in star colours, and sky colours, from the dusty orange-brown region at left, to the inky dark dustless region at far right.

– Alan, November 18 2014 / © 2014 Alan Dyer

 

The Soul of Cassiopeia


IC 1848, the Soul Nebula, in Cassiopeia

The Soul Nebula glows from within the constellation of Cassiopeia the Queen.

I shot this image last night, capturing an object prosaically known as IC 1848, but more popularly called the Soul Nebula.

It is often depicted framed with a companion nebula just “off camera” here to the right, called the Heart Nebula. Thus they are the Heart and Soul. Both shine on the eastern side of Cassiopeia the Queen.

Here I’m framing just the Soul, taking in some of the faint nebulosity to the left of the main nebula, including a tiny object called IC 289, a star-like planetary nebula at upper left.

I like this image for its variety of subtle colours, not only the reds and magentas in the bright nebula, but also in the dark sky around it from dim dust adding faint yellows, browns and even a touch of green.

The Soul Nebula lies 6,500 light years away in the Perseus Arm, the next spiral arm out from ours in the Milky Way. On northern autumn nights this region of the sky and Milky Way lies high overhead.

For the technically minded:

The image is a stack of 20 six-minute exposures, taken with a filter-modified Canon 5D Mark II at ISO 800. I was shooting through one of my favourite telescopes for deep-sky photography, the TMB (Thomas M. Back-designed) 92mm apo refractor, working at a fast f/4.4 using a Borg 0.85x field flattener and focal reducer.

I used one of Noel Carboni’s “Astronomy Tools” Photoshop actions to add the “diffraction spikes” on the stars. They are artificial (refractors don’t produce spikes on stars) but they add a photogenic touch to a rich starfield.

I shot this from the backyard of my New Mexico winter home.

– Alan, November 16, 2014 / © 2014 Alan Dyer

Truly Interstellar


M26 Open Cluster and NGC 6712 Globular Cluster

We gaze into the interstellar depths of the Milky Way through uncountable stars.

In this telescopic scene we look toward the Scutum Starcloud, and next spiral arm in from ours as we gaze toward the core of the Galaxy.

The field is packed with stars, seemingly crowded together in interstellar space. In fact, light years of empty space separate the stars, even in crowded regions of the Milky Way like this.

Two dense clusters of stars stand out like islands in the sea of stars. At lower right is Messier 26, an open cluster made of a few dozen stars. Our young Sun probably belonged to a similar family of stars billions of years ago. M26 lies 5,200 light years away.

At upper left is a condensed spot of light, made of hundreds of thousands of density packed stars in the globular cluster known only as NGC 6712. Though much larger and denser than M26, NGC 6712 appears as a tiny spot because of its remoteness – 23,000 light years away, a good part of the distance toward the centre of the Galaxy.

Look carefully (and it may not be visible on screen) and you might see a small green smudge to the left of NGC 6712. That’s a “planetary nebula” called IC 1295. It’s the blown off atmosphere of an aging Sun-like star. It’s what our Sun will become billions of years from now.

At top is a vivid orange-red star, S Scuti, a giant pulsating star nearing the end of its life.

A truly interstellar scene.

– Alan, November 9, 2014 / © 2014 Alan Dyer

 

 

Mars and M22


Mars and M22 Cluster

Mars shines near the globular star cluster Messier 22 in Sagittarius.

This week Mars has been passing near one of the brightest globular star clusters, M22. I caught the pair tonight, November 8, as they sank into the southwestern sky.

The two form a contrasting pair, with red Mars now 260 million kilometres away, far enough that its light takes 13 minutes to reach Earth. However, blue M22 lies so far away, toward the galactic core, that its light take 10,000 years to reach Earth.

Mars appeared closer to M22 earlier this week but tonight was the first night with a narrow window of dark sky between twilight and moonrise, allowing me to shoot the pair.

I shot the image through a telescope with a short focal length of 400mm, taking in a field of about 5 by 3 degrees, the field of high-power binoculars. The image is a stack of eight 2-minute exposures at f/4.5 with the TMB 92mm refractor and Canon 6D at ISO 800.

– Alan, November 8, 2014 / © 2014 Alan Dyer

Nebulas, Clusters and Starfields, Oh My!


Centre of the Galaxy Mosaic

There’s no more spectacular region of the sky than the Milky Way toward the centre of the Galaxy.

What a perfect night it was last night. After moonset between 2 and 3:30 a.m. I shot a series of images around the centre of the Galaxy area and stitched them into a big mosaic of the Milky Way.

The scene takes in the Milky Way from the Eagle and Swan nebulas at top left, down to the Messier 6 and 7 open clusters in Scorpius at bottom. Standing out is the large pink Lagoon Nebula left of centre and the huge region of dark dusty nebulosity popularly called the Dark Horse at right of centre. It’s made of smaller dark nebulas such as the Pipe Nebula and tiny Snake Nebula.

At upper left is the bright Small Sagittarius Starcloud, aka Messier 24, flanked by the open clusters M23 and M25. There are a dozen or more Messier objects in this region of sky.

The actual centre of the Milky Way is obscured by dark dust but lies in the direction just below the centre of the frame, amid one of the bright star clouds that mark this amazing region of sky.

I shot the images for this mosaic from a site near Portal, Arizona, using a 135mm telephoto lens and filter-modified Canon 5D Mark II riding on an iOptron SkyTracker to follow the stars. The mosaic is made of 6 panels, each a stack of five 3-minute exposures. They were all stacked and stitched in Photoshop CC. The full version is 8000 by 9000 pixels and is packed with detail.

I think the result is one of the best astrophotos I’ve taken! It sure helps to have Arizona skies!

– Alan, May 5, 2014 / © 2014 Alan Dyer

 

 

Our Neighbour Galaxy, the Large Magellanic Cloud


Large Magellanic Cloud (77mm Borg & 5DII)

One of our nearest galactic neighbours contains an astonishing collection of nebulas and star clusters.

This is the money shot — top of my list for targets on this trip to Australia. This is the Large Magellanic Cloud, a satellite galaxy of our Milky Way. At “just” 160,000 light years away, the LMC is in our galactic backyard. Being so close, even the small 77mm telescope I used to take this image resolves numerous nebulas, star clusters, and a mass of individual stars. The image actually looks “noisy” from being filled with so many stars.

I’ve oriented and framed the Cloud to take in most of its main structure and objects. One can spend many nights just visually exploring all that the LMC contains. It alone is worth the trip to the southern hemisphere.

At left is the massive Tarantula Nebula, a.k.a. NGC 2070. At upper right is the LMC’s second best nebula, the often overlooked NGC 1763, also known as the LMC Lagoon. In between are many other magenta and cyan tinted nebulas.

I’ve shot this object several times but this is my best shot so far I think, and my first with this optical system in several years.

I used a Borg 77mm aperture “astrograph,” a little refractor telescope optimized for imaging. It is essentially a 330mm f/4 telephoto lens, but one that is tack sharp across the entire field, far outperforming any camera telephoto lens.

This shot is a stack of six 10-minute exposures at ISO 800 with the filter-modified Canon 5D MkII camera. The autoguider worked perfectly. And yet, I shot this in clear breaks between bands of clouds moving though last night. The night was humid but when the sky was clear it was very clear.

Next target when skies permit: the Vela Supernova Remnant.

– Alan, March 25, 2014 / © 2014 Alan Dyer

 

A Dreamy Carina Nebula


Carina Nebula in Haze (77mm 5DII)

The Carina Nebula glows among the colourful southern stars.

I’ve shot this field many times over the years in visits to the southern hemisphere but never with a result quite like this. Last night the sky was hazy with high cloud but I shot anyway. The result is a “dreamy” rendition of the Carina Nebula and its surrounding clusters of stars. At upper left is the Football Cluster, NGC 3532, while at upper right is the Gem Cluster, NGC 3293.

As with my previous post, the haze brings out the star colours, filling the field with pastel shades. It is one of the finest fields in the sky, worth the trip down under.

Alas, skies have clouded up tonight with only a few bright stars and Mars shining through. And the forecast is for rain for the next few days. So I may get lots of writing done at my Aussie retreat.

As a technical note: I shot this with the little 77mm Borg Astrograph, essentially a 300mm f/4 telephoto lens that is tack sharp across a full frame camera, like the Canon 5D MkII I used here. It was riding on my Astro-Physics 400 mount and guided flawlessly with the Santa Barbara SG4 auto-guider. The image is a stack of four 8-minute exposures. All the gear, much of it stored here in Australia between my visits, is working perfectly.

– Alan, March 23, 2014 / © 2014 Alan Dyer

 

The Pleiades – The Stellar Seven Sisters


M45, the Pleiades Cluster (92mm 5DII)

The stars of the Pleiades sit amid a dusty sky in Taurus.

These are the famous Seven Sisters of Greek legend, known as the Pleiades. They are the daughters of Atlas and Pleione, who are also represented by stars in the cluster. Many cultures around the world tell stories about these stars, but in Greek tradition their appearance signalled the summer sailing season in the Mediterranean. The Pleiades first appear at sunset in the eastern evening sky in autumn and put in their last appearance in the western sky in spring.

One story has it they were placed in the sky to recognize their devotion to their father Atlas and his unending labour in holding up the heavens. They are the half-sisters of the Hyades, another nearby cluster of stars in Taurus. Other stories describe the Pleiades as the Seven Doves that carried ambrosia to the infant Zeus.

A seldom-used name now for this cluster is the Atlantides, from the plural form of Atlas, their father. Thus, these sisters gave their name to the Atlantic Ocean, a vast and uncharted sea until the 16th century. The term “atlas,” first used by Mercator for a book of maps, comes not from the Pleiades’ father but from a real-life king in Morocco who supposedly made one of the first celestial globes.

I shot this portrait of the Sisters a few nights ago, stacking a set of five 15-minute exposures with the TMB 92mm refractor and Canon 5D MkII at ISO 800. I processed the image to bring out the faint clouds of dust that pervade the area.

The Pleiades are passing through dust clouds in Taurus and lighting them up. The stars are embedded in dust, lit blue by the light of the hot stars. But even farther out you can see wisps of dust faintly illuminated by the light of the Pleiades.

The stars are thought to be about 100 million years old, quite young as stars go. They formed together in a massive nebula that has long since dissipated, and will travel together for another few hundred million years until the sister stars go their own way around the Galaxy. The stellar family that gave rise to so many legends around the world will be scattered to the stars.

– Alan, October 12, 2013 / © 2013 Alan Dyer

A Star-Filled Scene in Cassiopeia


M52 & NGC 7635 Bubble Nebula (92mm 5DII)

A star cluster and nebulas highlight a glorious starfield in Cassiopeia.

I shot this three nights ago on a very clear autumn evening. The telescope field takes in the star cluster Messier 52 at upper left, a cluster of 200 stars about 5000 light years away. It is one of the best objects of its class for viewing in small telescopes. Charles Messier found it in 1774 as part of his quest to catalog objects that might be mistaken for comets.

The brightest area of nebulosity below M52 is the Bubble Nebula, aka NGC 7635, found in 1787 by William Herschel. It’s an area of star formation marked by a central bubble of gas (just visible on the scale of my photo) being blown by the winds from a hot central star. The Bubble can be seen in amateur telescopes but is a tough target to spot.

Above the Bubble is a small bright nebula, NGC 7538.

Below the Bubble lies a larger claw-like nebula known only as Sharpless 2-157, an object that shows up only in photos.

In all, it’s a complex and beautiful field, set in the constellation of Cassiopeia the Queen.

A footnote for the technically minded: This is a stack of 5 x 15 minute exposures with a filter-modified Canon 5D MkII at ISO 800 shooting through a TMB 92mm apo refractor at f/4.8, mounted on an Astro-Physics Mach 1 mount guided by a Santa Barbara SG-4 autoguider.

– Alan, October 11, 2013 / © 2013 Alan Dyer

 

The Veil Nebula in Cygnus


NGC 6960 & 6992-5 Veil Nebula (92mm 5DII)

This is what’s left of a star that exploded thousands of years ago.

I shoot this object every year or two, so this is my 2013 take on the Veil Nebula. For last year’s see Star Death Site, a post from September 2012.

The Veil Nebula is a supernova remnant. The lacework arcs are what’s left of a massive star that blew itself to bits in historic times. This object, one of the showpieces of the summer sky for telescope users, is now high overhead at nightfall, off the east wing of Cygnus the swan.

I shot this a couple of nights ago using a 92mm-aperture refractor that provides a wide field of view to easily frame the 3-degree-wide extent of the nebula. The image is a stack of five 15-minute exposures with a filter-modified (i.e. red sensitive) Canon 5D MkII camera at ISO 800. Stacking the images helps reduce noise.

The colours in this object make it particularly photogenic, with a contrast of magenta and cyan. At right, a sharp-edged area of obscuring interstellar dust tints the sky brown and dims the stars.

– Alan, October 9, 2013 / © 2013 Alan Dyer

The Cocoon Nebula in Cygnus


Cocoon Nebula IC 5146 (92mm 5DII)

A cocoon of glowing gas sits at the tip of a dark cloud of interstellar dust.

It’s been months since I’ve shot more “traditional” astrophotos, meaning images of deep-sky objects through telescopes. But the last couple of nights have been excellent, and well-timed to the dark of the Moon.

This is the Cocoon Nebula in Cygnus, aka IC 5146. It is a cloud of gas about 4,000 light years away where new stars are forming. They are lighting up the gas to glow with incandescent pink colours.

The Cocoon sits at the end of snake-like dark nebula known as Barnard 168 which, in the eyepiece of a telescope, is usually more obvious than the subtle bright nebula. Photos like mine here, with long exposures and boosted contrast and colours, make nebulas look much brighter and more colourful than they can ever appear to the eye.

For the technically curious, I shot this with a 92mm diameter apochromatic refractor, the TMB 92, and a Borg 0.85x flattener/reducer, a combination that gives a fast f-ratio of f/4.8 with a very flat wide field. I also used my now-vintage filter-modified Canon 5D MkII at ISO 800. This is a stack of five 12-minute exposures, registered and median-combined in Photoshop to smooth out noise. All processing was with Adobe Camera Raw and Photoshop CC. The telescope was on an Astro-Physics Mach 1 mount, flawlessly autoguided with an SBIG SG-4 autoguider.

– Alan, October 6, 2013 / © 2013 Alan Dyer

 

King and Queen of the Sky


Cassiopeia and Cepheus (50mm 5DII) Sept 29, 2013

Cassiopeia and Cepheus reign over the autumn sky amid the Milky Way.

This is a photo from last night’s shoot, taken on a very clear autumn night with the Milky Way prominent across the sky. I shot sets of constellation images, among them this one framing Queen Cassiopeia and King Cepheus.

Cassiopeia is the well-known “W” pattern at lower left. Cepheus is harder to pick out – he’s a crooked square at right, topped by a tall triangle, like a child’s drawing of a house.

The Milky Way runs across the frame, peppered with red nebulas, from IC 1396 at far right in the bottom of Cepheus, to the NGC 7822 complex at centre, and the IC 1805 complex at far left. Lots of smaller nebulas dot the scene. At far left is the Double Cluster, two adjacent clumps of stars in the outer Perseus Arm of the Milky Way. Most of the deep-sky objects in this frame lie thousands of light years away in the next spiral arm out from the one we live in, or in the space between the two arms.

Most of the bright stars here are young blue stars. But a couple of exceptions stand out: yellow Shedar (or Alpha Cassiopeiae, the bottommost star in the W and an orange giant), and red Mu Cephei, at far right bordering the round IC 1396 nebula. That star is also known as Herschel’s Garnet Star. It is a red supergiant star 1400 times larger than our Sun and one of the most luminous stars in the catalog.

– Alan, September 30, 2013 / © 2013 Alan Dyer

 

Star-Making Clouds in Cygnus


Cygnus Nebulosity (135mm 5DII)

The centre of Cygnus is laced with an intricate complex of glowing gas clouds.

This is another shot from earlier this week, under ideal skies, in a view looking straight up into Cygnus the Swan. This is a telephoto lens shot of the amazing array of nebulas in central Cygnus, around the bright star Deneb.

At left is the North America and Pelican Nebulas. At right is the Gamma Cygni complex and the little Crescent Nebula at lower right.

Here we’re looking down our local Cygnus-Orion arm of the Milky Way into a region of star formation rich in glowing hydrogen gas and dark interstellar dust. These clouds lie about 1500 to 3000 light years away. Dotting the field are hot blue stars newly formed from the raw ingredients making stars in Cygnus.

At top, the clouds have a lacework appearance, like sections of bubbles. Perhaps these are being blown across space by the high-velocity winds streaming from the young stars.

– Alan, September 13, 2013 / © 2013 Alan Dyer

 

Log Cabin in the Milky Way


Milky Way over Log Cabin (July 11, 2013)

The summer Milky Way shines over a log cabin in the woods of the Cypress Hills.

This was the view this morning, at 2 a.m., as the Milky Way of northern summer shone over my vacation log cabin on the Reesor Ranch in Saskatchewan. After the clouds cleared the sky was beautifully dark for a while before the early dawn twilight came on.

The view here takes in the Milky Way from the Scutum star cloud above the trees to the dark dust clouds of northern Cygnus overhead. The trio of Summer Triangle stars, Deneb, Vega and Altair, flank the Milky Way.

This is a composite of five tracked and stacked images for the sky and one image for the foreground shot with the iOptron Skytracker running at half speed to minimize the blurring from the tracking motion. The lens was the 14mm Samyang at f/2.8.

– Alan, July 12, 2013 / © 2013 Alan Dyer

 

A Galaxy Floating in the Void


M109 in Ursa Major (130mm 60Da)

A galaxy 80 million light years away floats in the blackness of space near a star in the Big Dipper.

This is Messier 109, a bright spiral galaxy in Ursa Major, and within an eyepiece and camera field of the bright naked eye star Gamma Ursa Majoris. That’s the “bottom left” star in the bowl of the Big Dipper, so this is an easy galaxy to find with a telescope in the current spring sky.

Technically, this galaxy is classed as a barred spiral because of the way its spiral arms emerge from an elongated bar at the core of the galaxy. It is the brightest member of the Ursa Major Cluster of some 80 galaxies.

Springtime is galaxy time, no matter what hemisphere you live in. But for us in the northern half of the planet that means April and May. When we look up at this time of year into the evening sky we are looking out of the plane of our Milky Way galaxy and seeing into the depths of intergalactic space, populated by thousands of other galaxies. Most of the bright ones, like M109, are 20 to 100 million light years away. At its distance of 80 million light years, M109 lies a million times farther away from us than Gamma Ursa Majoris, a nearby blue star “just” 80 light years away and in our Galaxy.

I shot this last weekend though my 5-inch refractor with the Canon 60Da camera. Even with the telescope’s 800mm focal length it isn’t enough to really do justice to the intricate detail in galaxies like this. But the view does set the galaxy into its context, floating in the blackness of space.

– Alan, May 11, 2013 / © 2013 Alan Dyer

Skies of Enchantment – Summer Milky Way Rising


Summer Milky Rising over Adobe House (14mm 5DII)

If you lived here you’d be in astronomy paradise.

This is the summer Milky Way and galactic centre in Sagittarius and Scorpius rising before dawn early this morning. The setting is the Painted Pony Resort in New Mexico, and its adobe lodges.

There’s no more spectacular sight than this in the night sky, other than perhaps an all-sky aurora display. And they don’t get too many of those down here at 31° North in southern New Mexico.

This image is a stack of ten 3-minute exposures for the sky (to smooth out noise) but the ground is from just 2 of those exposures and is blurred because the camera was tracking the sky. Light from walkway lights, plus starlight itself, added just enough illumination to provide details in the foreground.

So to be clear – this is a real scene. The Milky Way has not been pasted onto a separate image of the foreground. However, colour and contrast have been boosted to bring out details your eye would not have seen had you been standing here early this morning in the frosty New Mexico night.

Again, as with my previous image taken earlier in the night, I used the new Samyang 14mm ultra-wide angle lens, at f/2.8. It works very well!

– Alan, March 11, 2013 / © 2013 Alan Dyer

A Luminous Starfield


M38 & IC 405-410-417 Complex (92mm 6D)

The Starfish and the Flaming Star combine to create a rich star field in the Charioteer.

I shot this last week, using a favourite small refractor that takes in a generous field of view for a telescope. In this case, it frames the star cluster at left called the Starfish Cluster, or better known as Messier 38. At right the large number 7-shaped patch of nebulosity is the Flaming Star Nebula, known by its catalog number as IC 405. At bottom, the nameless companion nebulas are IC 417 at left and IC 410 at bottom centre.

Of note is the colourful grouping of six stars at right called the Little Fish. It’s not a proper star cluster but an asterism, a chance alignment of stars that happens to look like something imaginative. David Ratledge presents a nice list and photo gallery of similar whimsical asterisms at his Deep-Sky.co.uk website.

The entire field is a rich hunting ground for the eyepiece or camera. You can find it these nights, in winter from the northern hemisphere, straight overhead in the evening, in the middle of Auriga the Charioteer.

For this portrait I shot and stacked eight 7-minute exposures at ISO 800 using a filter-modified Canon 6D on my TMB 92mm apo refractor at f/4.8.

Happy Valentine’s Day!

– Alan, February 14, 2013 / © 2013 Alan Dyer

 

The Subtle Glow of Comet Dust


Zodiacal Light rfrom Home (Feb 8, 2013)

Out of the skyglow from lights and the remains of twilight rises a tapering pyramid of light. It’s one of the night sky’s most subtle sights for the naked eye.

This is the Zodiacal Light, and I’ve been trying to capture it in the evening sky from home for a number of years. Last night was a good night for it. The sky was very transparent, for the first couple of hours at least. An ultra-wide angle lens allowed me to capture the Light in context with the wider sky, towering out of the southwest at right, reaching up to the Pleiades and Jupiter high in the centre of the frame. The Milky Way is at left. Everyone knows the Milky Way but the Zodiacal Light is less famous.

It’s visible only in the hour or two after sunset or before sunrise. Late winter and spring are the best times to see it in the evening sky. That’s when the ecliptic – the plane of the solar system where the planets lie – is tipped up at its highest angle above the horizon putting it above obscuring haze. The Zodiacal Light lies along the ecliptic because it is part of our solar system, not in our atmosphere. It is sunlight reflected off dust orbiting in the inner solar system that’s been cast off over thousands of years by comets passing through. It is brightest closest to the Sun and fades out at greater angles away from the Sun. Thus its tapering appearance in my sky as the photo shows, very much as my eye saw it.

It takes a good night at a dark site to see the Zodiacal Light. But take a look at the next dark of the Moon. You’ll be surprised at how easy it is to see once you know what to look for.

– Alan, February 9, 2013 / © 2013 Alan Dyer

 

The Beautiful Belt of Orion


Belt of Orion & B33 Horsehead Nebula (92mm 6D)

Everyone knows the Belt of Orion, but only the camera reveals the wealth of colours that surround it.

I shot this Friday night, February 8, under very clear sky conditions.

While I used a telescope, it had a short enough focal length, about 480mm, that the field took in all three stars in the Belt: from left to right, Alnitak, Alnilam, and Mintaka. All are hot blue stars embedded in colourful clouds. The most famous is the Horsehead Nebula, running down from Alnitak at left. Above the star is the salmon-coloured Flame Nebula. All manner of bits of blue and cyan nebulas dot the field, their colour coming from the blue starlight the dust reflects.

Dimmer dust clouds more removed from nearby stars glow with browns and yellows. At left, a large swath of sky is obscured by gas and dust simmering in dull red. The entire field is peppered with young blue stars.

It is certainly one of the most vibrant regions of sky, though only long exposures and image processing bring out the colours.

This is another test shot with a new Canon 6D that has had its sensor filter modified to transmit more of the deep red light of these types of nebulas. The camera works very well indeed!

– Alan, February 8, 2013 / © 2013 Alan Dyer

Snapshots of Starlife


IC 443 Jellyfish Nebula & M35 (92mm 6D)

This one image frames examples of both the beginning and end points of a star’s life.

I shot this last night, February 6, 2013, capturing a field in the constellation of Gemini the twins. At upper right is the showpiece star cluster known as Messier 35. It’s a collection of fairly young stars still hanging around together after forming from a cloud of interstellar gas tens of millions of years ago. M35 lies about 2,800 light years from Earth, on the other side of the spiral arm we live in. Just below M35 you can see another smaller and denser cluster. That’s NGC 2158, about five times farther away from us, thus its smaller apparent size. Both are objects that represent the early stages of a star’s life.

At lower left is an object known as the Jellyfish Nebula, for obvious reasons. The official name is IC 443. It’s the expanding remains of a star that blew up as a supernova anywhere from 3,000 to 30,000 years ago. What’s left of the star’s core can still be detected as a spinning neutron star. You need a radio telescope to see that object, but the blasted remains of the star’s outer layers can be seen through a large backyard telescope as a shell of gas. It is expanding into the space between stars – the interstellar medium – ploughing into other gas clouds. The shockwave from its collision with other nebulas may trigger those clouds to collapse and form clusters of new stars. And so it goes in the Galaxy.

For this portrait of stellar lifestyles, I used a 92mm apochromatic refractor and a new Canon 6D camera, one that has had its sensor filter modified to accept a greater range of deep red light emitted by hydrogen nebulas. The image is actually a stack of 12 exposures with an accumulated exposure time of 80 minutes.

– Alan, February 7, 2013 / © 2013 Alan Dyer

An Orion Portrait from Alberta


Orion in Porttrait Format

He’s certainly the sky’s most photogenic mythological figure. Here’s my full-length portrait of Orion the hunter, captured from Alberta.

I’ve shot him many times before but this was a new combination of gear: the Canon 60Da camera and the Sigma 50mm lens, nicely framing the hunter in portrait format. This version of Orion isn’t as deep as the one I took last month from Australia. But skies were darker there, and I used my filter-modified Canon 5D MkII for his Oz portrait, a camera which picks up more faint red nebulosity than does the 60Da, Canon’s own specialized DSLR camera for astronomy. The 60Da does do a very good job though, much better than would a normal DSLR.

For this shot, as I do for many constellation images, I layered in exposures taken through a soft-focus filter, the Kenko Softon, to enlarge and “fuzzify” the stars! It really helps bring out their colours, contrasting cool, orange Betelgeuse with the hot blue-white stars in the rest of Orion.

I shot this January 4 on a fine clear winter night, the classic hunting ground for Orion.

– Alan, January 11, 2013 / © 2013 Alan Dyer

Jupiter Amid the Clusters of Taurus


Jupiter in Taurus (January 4, 2013)

Look up on a clear night this season (winter for us in the northern hemisphere) and you’ll see a bright object shining in Taurus the bull. That’s Jupiter.

This year Jupiter sits in a photogenic region of the sky, directly above the stars of the Hyades star cluster and yellow Aldebaran, the brightest star in Taurus. Above and to the west (right) of Jupiter is the blue Pleiades star cluster.

Over the course of January 2013 you’ll be able to see Jupiter move a little further west each night (to the right in this photo) away from Aldebaran and toward the Pleiades. Jupiter will stop its retrograde motion on January 30. After that it treks eastward to again pass above the Hyades and Aldebaran (returning to where it is now) in early March.

Jupiter’s proximity to Aldebaran and the Hyades makes it easy to follow its retrograde loop over the next few weeks. It’s an easy phenomenon to watch, but explaining it took society hundreds of years and the ultimate in paradigm shifts in thinking, from the self-important arrogance that Earth – and we – were the centre of the universe, to the Sun-centered view of space, with Earth demoted to being just one planet orbiting our star.

I took this image Friday night, January 4, from home as my first astrophoto upon returning to Canada from Australia. It’s a combination of two sets of images: one taken “straight & unfiltered” and one taken through a soft-focus filter to add the glows around the stars and central, brilliant Jupiter. I then blended the filtered images onto the normal images in Photoshop with the Lighten blend mode.

– Alan, January 5, 2013 / © 2013 Alan Dyer

A Truly Amazing Sky — A New Year’s Gift


Timor Cottage Panorama #3

As we end 2012 and start a new year, I wish everyone a very happy 2013 and leave you with this view of a very amazing sky.

This is a 360° panorama of the Milky Way over Timor Cottage on a very clear night in mid-December in New South Wales, Australia. May all your skies be as wonderful and as inspiring as this in the coming year.

Indeed, we have some potentially remarkable sights to look forward to, with the prospects of two bright comets in 2013: Comet PANSTARRS in March and Comet ISON in November and December.

Let’s hope for more amazing skies in 2013. Keep looking up!

– Alan, December 31, 2012 / © 2012 Alan Dyer

Zooming into Canis Major – #3


NGC 2359 Thor's Helmet NebulaIn the third instalment in my trilogy of Canis Major zooms, I present this close-up of another neat nebula in the Great Hunting Dog, called Thor’s Helmet.

You can tell just by the colour that this is a different type of nebula than the typical red hydrogen gas clouds, such as the Seagull Nebula of my previous post. Yes, this is glowing gas but this nebula originates from a different source than most. Rather than being a site where stars form this is a nebula surrounding an aging star, a massive superhot star that is shedding shells of gas in an effort to lose weight – or mass as we should say.

Intense winds from the star blow the gas into bubbles, and cause it to fluoresce in shades of cyan. The central star is one of a rare stellar type called a Wolf-Rayet star, named for the pair of French astronomers who discovered this class of star in the 19th century. WR stars are likely candidates to explode as supernovas.

This particular Wolf-Rayet nebula, catalogued as NGC 2359, has a complex set of intersecting bubbles that, through the eyepiece, do take on the appearance of a Viking helmet with protruding horns, like you see in the Bugs Bunny cartoon operas! It’s a neat object to look at with as big a telescope as you can muster. And, as you can see, it’s rather photogenic as well, embedded in a rich field with faint star cluster companions.

– Alan, December 28, 2012 / © 2012 Alan Dyer

Zooming into Canis Major – #2


IC 2177 Seagull Nebula Complex

Zooming in closer yet again to the field in Canis Major I showed in my previous post, I’m now framing the large nebula known as the Seagull. Perhaps you can see him flying through the stars.

The catalog number for this object is IC 2177, but the bright round nebula at right (the head of the Seagull?) is object #1 in the catalog of Australian astronomer Colin Gum. It’s also object #2327 in the familiar NGC listing that all stargazers use.

Some of this nebulosity is just visible through a small telescope, especially with the aid of a nebula filter than accentuates the emission lines – the colours – emitted by these kinds of glowing gas clouds.

This is certainly a photogenic field, with a nice mix of pinks, blues, purples and deep reds.

I used my 4-inch (105mm aperture) f/5.8 apo refractor to shoot this target, so the field is fairly narrow, framing what a telescope would show at very low power.

(FYI – The image info listed at left, automatically picked off the image’s EXIF data by the WordPress blog software, fails to record the focal length of the optics properly, as I didn’t use a standard camera lens but a telescope the camera doesn’t know about.)

I’ve been after a good shot of this object for some years, but haven’t been successful until this past observing run in Australia, in December 2012. While I can see and shoot the Seagull Nebula from home in Alberta, it’s always very low in my home sky. From Australia the challenge was framing the field with the Seagull overhead at the zenith. Just looking through the camera aimed straight up took some ground grovelling effort. Plus avoiding having the telescope hit the tripod as it tracked the object over the hour or so worth of exposures – typically 4 to 5 that I then stack to reduce noise.

– Alan, December 28, 2012 / © 2012 Alan Dyer

 

Zooming into Canis Major – #1


M50 - M46/M47 Area Bino Field

My last post featured a wide view of Canis Major. Here, we zoom in closer to one of the most interesting regions in that constellation, filled with nebulas and clusters.

The prominent red arc is the Seagull Nebula, aka IC 2177. Above and to the right of the Seagull is a clump of stars called Messier 50, which lies over the border in the constellation of Monoceros the Unicorn.

At the lower left edge of the frame sits a pair of dissimilar star clusters, Messier 46 (the left one) and Messier 47 (the right one). M46 is a dense rich cluster of stars while M47 is brighter but looser and more scattered.

Several other non-Messier clusters punctuate the field. This is a great area of sky to explore with binoculars.

Just below centre you might see a small green-blue patch. That’s the nebula called Thor’s Helmet, or NGC 2359, a fine telescopic object.

If you get a clear night this season when the Moon is out of the way and you can head to a dark sky, Canis Major, the Hunting Dog, is a great hunting ground for deep-sky fans.

As the data at left shows, I shot this with a 135mm telephoto lens, giving a field of view similar to what binoculars would show.

– Alan, December 28, 2012 / © 2012 Alan Dyer

Canis Major and the Dog Star


Canis Major from Australia (50mm 5DII)

Shining in the southern sky these nights are the stars of Canis Major, the big hunting dog of Orion the Hunter. Among them is the famous Dog Star, Sirius, the brightest star in the night sky.

Can you see a dog outlined in stars? Sirius marks his head – or it is sometimes depicted as a jewel in his collar. His hind legs and tail are at the bottom of the frame.

I shot this earlier this month from Australia, where Sirius and Canis Major stand high overhead. From northern latitudes you can see these stars due south low in the sky about midnight. Sirius is hard to miss, often sparkling through many colours as our atmosphere distorts its light. But as the photo shows, it is really a hot blue-white star. While it is intrinsically a bright star, much of its brilliance in our sky comes from its proximity, only 9 light years away from us.

For this portrait of the celestial canine I used a 50mm “normal” lens. The atmosphere provided some natural haze this night, to add the glows around the stars accentuating their colours.

This area of sky also contains several nebulas, notably the red arc of the Seagull Nebula to the left of Sirius. Below Sirius you can also see the star cluster Messier 41, a good target for binoculars.

Toward the left edge of the frame you can see a pair of star clusters, Messier 46 and Messier 47, two other excellent binocular objects in the Milky Way, which runs down the frame to the left of Canis Major. The dog is just climbing out of the Milky Way after a swim in this river of stars.

– Alan, December 28, 2012 / © 2012 Alan Dyer

 

The Christmas Tree Cluster


NGC 2264 Christmas Tree Cluster & Cone Nebula

 

The current night sky contains another seasonal sight, a cluster of stars called the Christmas Tree Cluster. Turn the image upside down and you might see it!

The bright star lies at the base of the Christmas tree and at the bottom of a tall triangle of blue and yellow stars that outlines – or decorates – the tree. At the top of the tree sits the dark Cone Nebula. The Tree also encompasses a bright blue dusty nebula reflecting the light of nearby stars and swirls of pink glowing hydrogen. At right sits a rich cluster of stars dimmed yellow by intervening dust. At bottom (south) in this photo you can also see a small V-shaped object. That’s Hubble’s Variable Nebula, a dust cloud studied by Edwin Hubble, one that varies in intensity with fluctuations in the main star embedded at its tip.

This rich area of sky lies above (north of) the subject of my previous post, the Rosette Nebula in the constellation of Monoceros the Unicorn. Very little of this is visible to the eye. The magic of photography is how it coaxes detail out of the sky that the eye alone cannot see.

– Alan, December 27, 2012 / © 2012 Alan Dyer

 

A Cosmic Wreath in the Sky


NGC 2237 Rosette Nebula

This is the Rosette Nebula, a celestial wreath 5,000 light years in the northern winter sky.

It is one of the most photogenic of nebulas, but is barely visible to even an aided eye as a ghostly grey arc of light around the central star cluster. Winds from the group of hot stars at the centre of the Rosette are blowing a hole in the cloud, creating the wreath-like shape of the Rosette.

While I shot this earlier this month from Australia, the Rosette lies far enough north in the constellation of Monoceros that northerners can see this cosmic wreath on any dark and clear winter night. It makes a beautiful decoration in our holiday sky.

Happy holidays to all!

– Alan, December 26, 2012 / © 2012 Alan Dyer

The Amazing Orion Nebula


Orion Nebula Complex, M42, M43, NGC 1973-5-7

My Australian nights are proving to be frequently and thankfully clear enough that I’ve got the luxury of shooting some familiar “home sky” objects. This is the famous Orion Nebula in the Sword of Orion, about 1500 light years away.

I’ve shot this nebula many times from the northern hemisphere but my Australian skies are darker than at home, and the nights a lot warmer than when this object is up in our winter sky.

The Orion Nebula is a complex consisting of Messier 42, the main nebula, M43, a small nebula attached to the north (above) and the bluish Running Man Nebula (can you see his dark figure?) at top that is officially catalogued as NGC 1973-5-7. Together, these make up the largest region of star formation in our corner of the Milky Way. It’s easy to see with the unaided eye on a dark night.

To shoot this, I blended three different exposures, short (4 x 1 minute), medium (4 x 5 minutes) and long (4 x 15 minutes), to preserve all the details from the intensely bright core our to the faint tendrils extending into deep space. I stacked the 4 frames taken at each of the exposure times, then blended those stacks using masks in Photoshop CS6 (and its wonderful and editable Refine Mask function) to mask out the overexposed area of the longer exposure and let the shorter exposure content shine through. The result is that the core still shows the little cluster of stars, the Trapezium, and the characteristic green tint of the core. But I applied lots of Curves to bring out the fainter bits and swirls in the periphery.

I shot this through my Astro-Physics Traveler 105mm refractor at f/5.8 using the filter-modified Canon 5D MkII camera, at ISO 400. This turned out to be certainly my best shot of Orion yet in my library.

– Alan, December 13, 2012 / © 2012 Alan Dyer

Southern Milky Way in the Blue of Dawn


Southern Milky Way at Dawn (December 2012)

At the end of a nearly perfect night of southern stargazing, I shot this wide-angle portrait of the southern Milky Way embedded in the deep blue of morning twilight.

In December at dawn, the southern Milky Way extends from Orion (at the extreme right) down through Canis Major, Puppis and Vela (where you can see a large faint red bubble-shaped nebula high in the south) then continues east (left) into Carina and Crux. The red Carina Nebula sits in the Milky Way and the Southern Cross is at left, rising before the two Pointer Stars, Alpha and Beta Centauri. The Magellanic Clouds sits above the cottage I’m using as my southern hemisphere home for stargazing while I am in Australia.

– Alan, December 12, 2012 / © 2012 Alan Dyer

 

Southern Spectacular in Carina


Carina Nebula

The Carina Nebula ranks as one of the most spectacular sights in the southern sky.

I shot this last night under perfect conditions. I’ve shot this nebula many times before but had to have a go at it again – I think this version is the best yet of many I’ve taken over the years of coming to the southern hemisphere to shoot the sky. I shot this through my 4-inch apo refractor with a filter-modified Canon 5D MkII camera. It’s a stack of five 12-minute exposures at ISO 400.

This massive nebula is the site of loads of star formation, and home to one massive young star, Eta Carinae, that is a prime candidate for a supernova explosion sometime soon. That will certainly stir things up in Carina. This object sits over 6,000 light years away in the next spiral arm in from ours, the Carina-Sagittarius Arm of the Milky Way.

Through the telescope it fills the field with intricate shades of grey — the colours show up only in photos – with one bright yellow star at the centre, Eta Carinae itself shrouded in the golden-hued nebula it cast off during its last explosive outburst in the 1840s.

Like the Large Magellanic Cloud, this is one object worth the trip to southern skies just to see for yourself.

– Alan, December 12, 2012 / © 2012 Alan Dyer

In the Lair of the Tarantula Nebula


NGC 2070 Tarantula Nebula area of LMC (105mm 5DII)

This is one of the most spectacular areas of the southern sky, around the lair of the Tarantula Nebula.

I shot this close up of the Large Magellanic Cloud last night, December 10, 2012 to frame the most interesting part of the LMC, the massive Tarantula Nebula. This star-forming region is much larger than any in our Milky Way, yet exists in a small dwarf galaxy that is a satellite of our Milky Way. But tidal forces from our Milky Way are torturing the Magellanic Clouds and stirring up massive amounts of star formation. If the Tarantula were as close to us as is the Orion Nebula some 1500 light years from us, the Tarantula would cover 30° of sky and cast shadows at night. Good thing perhaps that the wicked Tarantula is 160,000 light years away.

I shot this with my 105mm apo refractor. It’s a stack of 5 x 12 minute guided exposures, using the filter-modified Canon 5D MkII camera.

This is a wonderful region of sky to explore with any telescope. I had a great look at it through my 10-inch Dobsonian reflector last night. Well worth the trip to the southern hemisphere to see!

– Alan, December 11, 2012 / © 2012 Alan Dyer

 

Depth of Detail in the Large Magellanic Cloud


Large Magellanic Cloud (135mm)

If this was the only unique object in the southern sky that we couldn’t see from up North, then it would still be worth travelling south of the equator to see the southern sky.

This is the Large Magellanic Cloud, a satellite galaxy to our Milky Way. Being “just” 160,000 light years away (as opposed to millions of light years for most galaxies) this object is large (it fills the field of binoculars) and is rich in detail. Just look at all the pinkish nebulas dotting its ragged structure. The biggest is near the bottom, the massive Tarantula Nebula. Through a telescope there is so much to see in this object it takes careful comparisons with charts and atlases over several nights just to figure out what all the nebulas and clusters are in the eyepiece. It is a deep-sky observer’s dream object. While several professional astronomers have made their careers studying just the Magellanic Clouds.

Once classed as an irregular, ragged galaxy, the “LMC” is now thought of as a barred spiral. I think this photo suggests the two spiral arms coming off the top and bottom of the central elongated bar.

I shot this last night, under a perfect night of viewing in Coonabarabran, Australia, using a 135mm telephoto lens. The field is similar to what you see in binoculars though the long exposure (this is a stack of ten 5-minute tracked exposures) brings out more detail than the eye can see. Compare this wide view with a higher magnification shot I took two years ago from the same location. Both are good but I like this wider view better as it sets this big object into the celestial frame of the surrounding night sky.

– Alan, December 6, 2012 / © 2012 Alan Dyer

Regal Colours of Cassiopeia


 

Sitting on the border of Queen Cassiopeia and King Cepheus is this royal cloak of pinks and reds.

Too faint to see even in a small telescope, the main cloud of nebulosity is called NGC 7822, with a companion cloud below known as Cederblad 214. Rather cold names for a stunning region of space.

I love the colours in this field. The camera I use is modified to bring out the reds of glowing hydrogen but also nicely picks up blues and purples, which mix to provide subtle shades of pink and magenta. There are even yellows and greens from dust clouds.

Yes, I’ve certainly punched up the colour and contrast quite a bit from what came out of the camera, but I tried to retain a “natural” colour balance, not skewing the palette too far to the deeply saturated monotone red I see in some images of nebulas.

I shot this Saturday night, October 6, from my backyard on a fine autumn night for stargazing and star shooting. It’s a stack of eight 12-minute exposures, “median” combined to eliminate the satellite trails that crossed several frames.

– Alan, October 6, 2012 / © 2012 Alan Dyer

City of Stars


Some 3 billion years from now we are going to collide with this galaxy.

This is the famous Andromeda Galaxy, now 2.5 million light years from us but getting closer by the day! Andromeda, a.k.a. Messier 31, is the most distant object readily visible to the naked eye. It now shines high overhead for us in the northern hemisphere.

I asked Siri, my iPad assistant, how many stars are in the Andromeda Galaxy, and she said one trillion. She’s right. Recent estimates put Andromeda’s stellar population at 3 or 4 times that of our own Milky Way Galaxy. It’s also bigger. Measuring from the outermost extremities of the disk gives a diameter of over 200,000 light years, twice the size of our home galaxy.

I took this shot last week. It’s stack of five 15-minute exposures with a new Lunt 80mm refractor. The long exposures bring out the faint halo of stars extending beyond the main bright disk, the part you see in a telescope. You can also see Andromeda’s two close companion galaxies: M32, looking like a fuzzy star below the core; and M110, the elliptical galaxy above the core and connected to the main galaxy by a bridge of faint stars.

– Alan, September 27, 2012 / © 2012 Alan Dyer

Star Death Site


This is the graveyard of where a star died at the dawn of civilization.

The Veil Nebula, made of several fragments, is the remains of a star that exploded as a supernova some 5000 to 8000 years ago. With a telescope you can see this deep sky wonder high overhead these nights, in Cygnus the swan. A decent sized telescope, say 15 to 25cm diameter, can show a lot of the detail recorded here, but only in black-and-white. It takes a photo to pick up the magentas, from glowing hydrogen, and cyans, from oxygen being excited into shining by the shockwave created as the expanding cloud ploughs into the surrounding interstellar gas.

The whole complex is called the Veil Nebula but the segment at right passing through the star 52 Cygni is called the Witch’s Broom Nebula.

I shot this from home a couple of nights ago during a continuing run of typically fine fall weather, which usually brings the best nights of the year for astronomy. For this shot I used a new Lunt 80mm apochromatic refractor on loan for testing. It works very well! This is a stack of five 15-minute exposures.

– Alan, September 22, 2012 / © 2012 Alan Dyer

Goodness Gracious! A Great Ball of Stars!


This is what half a million stars look like when packed into one big ball. 

This is the globular star cluster called Messier 22, in Sagittarius. It’s the biggest and best such object visible from Canadian latitudes, though it always sits low in our summer sky. M22 is one of 150 or so such spherical clusters of stars that orbit our Milky Way. This one sits 10,000 light years away from us, toward the centre of the Galaxy. Those half million stars are packed into a sphere 100 light years across. In our sky it appears as big as the Full Moon, though not as bright of course. But just imagine the sky if you can view it from the centre of M22. The heavens would be ablaze with stars. 

I shot this with the 130mm refractor at f/6. It’s a stack of just three 4-minute exposures with the Canon 7D. Though M22 was low above the southern horizon from the Cypress Hills where I shot this, the final image turned out pretty well. 

– Alan, August 30, 2012 / © 2012 Alan Dyer

 

The Subtle Shades of Cepheus


The Milky Way in Cepheus presents a palette of colours revealed in long exposures.

This binocular-sized field contains the large magenta nebula IC 1396, a site of star formation. On its northern (upper) edge shines the orange star Mu Cephei, otherwise known as Herschel’s Garnet Star, for its very red appearance in the eyepiece. It is a bloated red supergiant, one of the largest stars known. A few other stars in the field are younger blue giants. Faint wisps of red hydrogen fill the field (the faint crescent at right is Sharpless 129, left of centre is Sharpless 132, at top left is NGC 7380). Diagonally along the Milky Way lie dark, yellow-tinted dust clouds. The darkest patch at centre is the Barnard 169/170/171 complex. These contrast with the dust-free blue starfields of the Milky Way at left.

This is a stack of five 5-minute exposures with the 135mm telephoto and Canon 5D MkII camera, which has been filter modified to record the faint red nebulas better than a stock camera.

– Alan, August 25, 2012 / © 2012 Alan Dyer

 

Star Gazing


Happiness is a big telescope under a dark sky.

This is Regina astronomer Vance Petriew, gazing skyward at the Milky Way in Cassiopeia. Vance is the discoverer of Comet 185/P, aka Comet Petriew. This year, his comet returned to the August sky as a faint glow in Gemini, close to where it was when Vance found it exactly 11 years to the day before this image was taken, and at the very same spot in the campsite at Cypress Hills Interprovincial Park in Saskatchewan.

We all revelled in the Saskatchewan comet’s return, staying up till 4 am to see it through Vance’s 20-inch telescope, a reflector made by the small company called Obsession. (When you have an Obsession, you are a serious observer!) Enjoying the view early that morning before dawn were  Vance’s three daughters, only one of whom was around 11 years ago and then as a baby. But this year even the four-year-old was able to see Dad’s comet up close.

At the afternoon talks Vance recounted the story of how the comet’s discovery changed his life, and led to immense changes at the Park. As a result of the media and political attention the comet brought, the Park has become a Dark Sky Preserve, one of the first in Canada, leading a nationwide movement, while astronomy programming is now an integral part of the Park’s interpretive programs, as it is becoming at other provincial and national parks. There is now a permanent public observatory and lecture hall nearby in Cypress Hills, just a short walk away from where the comet was found.

Comets can have quite an impact!

— Alan, August 24, 2012 / © 2012 Alan Dyer

A Cloud of Stars in Scutum


This is a binocular-sized gulp of sky in the northern summer Milky Way. Countless stars form a bright patch in the Milky Way called the Scutum Starcloud, named for the odd little constellation of Scutum the Shield that contains it.

Visible to the naked eye, this star cloud is a rich area for binoculars or a small telescope. One favourite object of stargazers lies embedded in the star cloud and can be seen here as a bright clump of stars at left of centre. That’s the Wild Duck Cluster, or Messier 11, a dense and populous cluster of stars within the already star-packed Scutum Starcloud. Look in this direction into the Milky Way and you are looking toward the next spiral arm in from ours, some 6,000 light years away.

The immensity of stars in just this small area of sky is hard to fathom. That’s why it’s called deep space!

– Alan, August 9, 2012 / © 2012 Alan Dyer

 

A River of Starlight and Dust


 

Look up on a dark summer night in the northern hemisphere and you see a river of stars flowing across the sky.

This is the Milky Way, a glowing mass of millions of distant stars populating the spiral arms of the Galaxy we live in. Lining the arms are lanes of dark interstellar dust, seen here splitting the Milky Way in two from the bright red North America Nebula at top, down to the core of the Galaxy in Sagittarius on the horizon. The dust is the soot created in stars and blown into space to form a new generation stars and planets.

This ultra-wide-angle scene takes in almost the entire summer Milky Way from the southern horizon to beyond the zenith overhead at top. I shot this a couple of nights ago from my rural backyard on a particularly transparent and dark night. It was heaven on Earth.

— Alan, July 26, 2012 / © @ 2012 Alan Dyer

 

Chariot of the Sky


Auriga the Charioteer rides high across the northern winter sky these nights. This is a wide-field image I took last week of the constellation that now shines overhead from northern latitudes.

My image takes in all of Auriga, the pentagon-shaped charioteer of Roman mythology, as well as the feet of Gemini the twins, spanning a wide area of the winter Milky Way. Sprinkled along this bit of Milky Way you can see a few clusters of stars. They include four of the best open star clusters in the catalogue of Charles Messier: M35 in Gemini at bottom, and M36, M37 and M38 in Auriga at centre, all wonderful targets for a small telescope. Some of these targets lie in the next spiral arm out from the one we live in.

The star colours show up nicely here, with the brightest star at top appearing a little off white. That’s Capella, 42 light years away and classified as a type G “yellow” star not unlike our own Sun in temperature but much larger – a giant star. Indeed, it is really two yellow-giant stars in close orbit around each other. It’s interesting that Capella doesn’t really show up as yellow. Just like our Sun does to our eyes, Capella appears white because it still emits such a broad range of colours that even though its peak energy does fall in the yellow part of the spectrum, all the other colours remain strong enough that the star looks white to our eyes. Remember, our eyes evolved under the light of a type G star to see all the colours of the spectrum from red to blue.

Only the cool red giant stars take on a yellow or orange hue to our eyes, and to the camera. You can see a few in this image, as well as hot blue stars. The pinky red bits are nebulas in the Milky Way – clouds of hydrogen gas emitting deep red light.

When we look in this direction in the Milky Way we are looking out toward the edge of our Galaxy, exactly opposite the galactic centre.

– Alan, February 21, 2012 / © 2012 Alan Dyer

The Rose of Winter


While I took this shot three weeks ago, I’ve only just got around to processing it. This is a nebula-filled region of the northern winter sky in the constellation of Monoceros, the unicorn.

The highlight is the rose-like Rosette Nebula at bottom, an interstellar flower of glowing hydrogen where new stars are forming. Above it, at centre, is a mass of pink, blue and deep red nebulosity that forms the Monoceros Complex. All lie in our local corner of the Milky Way, in a spiral arm fragment called the Orion Spur, a hotbed of star formation.

This field, shot with a 135mm telephoto lens, sits to the left of Orion and spans about a hand width at arm’s length. It would take a couple of binocular fields to contain it. Next on my astrophoto agenda – shooting some close ups of selected bits of Monoceros, shots that have eluded me till now.

— Alan, February 12, 2012 / © 2012 Alan Dyer

Celestial Pinks and Blues


 

Who says the dark night sky isn’t colourful? Of course, to the naked eye it mostly is, with the darkness punctuated only with a few red, yellow and blues stars. But expose a camera for long enough and all kinds of colour begins to appear.

This region is above us now, in the Northern Hemisphere evening sky for mid-winter. It’s the boundary area between Taurus and Perseus. Below are the vivid blues of the hot young Pleiades star cluster in Taurus. At top, just squeezing into the frame, is the shocking pink of the California Nebula, a glowing cloud of hydrogen gas in Perseus.

But between are the subtle hues of faint nebulosity weaving all through the Perseus-Taurus border zone. Below are faint cyans and blues from dust clouds reflecting the light of the Pleiades stars. In the middle are the yellow-browns of dark dust clouds hardly emitting light at all, but snaking across the frame to end in a complex of pink and blue straddling the border collectively known as IC 348 and IC 1333. At top, the glowing hydrogen gas of the California emits a mix of red and blue wavelengths, creating the hot pink tones, but fading to a deeper red to the left as the nebula thins out to the east. Throughout, hot blue stars pepper the sky and help illuminate the dust and gas clouds which will likely form more hot stars in the eons to come.

I took this shot last Wednesday night, on one of the few clear, haze-free nights of late. This is a “piggybacked shot,” with the Canon 5D MkII camera going along for the ride on one of my tracking mounts. This final shot is a stack of five 6-minute exposures, highly processed to bring out the faint clouds barely brighter than the sky itself. The camera was equipped with a 135mm telephoto lens, giving a field of view a couple of binocular fields wide. Hold out your hand and your outstretched palm would nicely cover  this area of sky. But only the camera reveals what is actually there.

— Alan, January 29, 2012 / Image © 2012 Alan Dyer

Set the Controls for Triangulum


 

Spiral galaxies are icons of deep space. This one is a classic. This is the Triangulum Galaxy, named for its home constellation. Amateur astronomers also know it as M33, the 33rd entry in Charles Messier’s catalog of deep sky objects compiled in the 1780s. To Messier, object #33 was another fuzzy spot he and others might confuse for comets, the objects astronomers of the day were really after.

It wasn’t until 1850 that the Earl of Rosse, observing with his monster Leviathan of Parsonstown, a 72-inch reflector telescope, managed to see M33 as something more than a nebulous glow. He saw what the photo clearly shows — spiral arms swirling around a central core. However, in those days, such “spiral nebulae” were thought to be whirlpools of gas where stars and solar systems were forming.

It wasn’t until the 1920s, with the work of Edwin Hubble, that objects like M33 were proven to be other galaxies like our Milky Way, each composed of billions of stars.

We now know the Triangulum Galaxy lies about 3 million light years away, and is about half the size of our Milky Way. That makes it the third largest member of our Local Group of galaxies, after our own Milky Way and the famous Andromeda Galaxy.

For this shot of M33, taken September 25, I stacked 6 images, each a 12-minute exposure at ISO 800 and f/6, shot with my Astro-Physics 130mm refractor and Canon 7D camera. Visible along the galaxy’s spiral arms you can see some of the reddish and cyan-coloured nebulas that are sites of active star formation in M33.

— Alan, Oct 7, 2011 / Image © 2011 Alan Dyer

The Stellar Triangle of Summer




When the Summer Triangle sinks into the west, we know summer has come to an end. While the stars of the Summer Triangle are now high overhead from northern latitudes as the sky gets dark, by late evening the Summer Triangle is setting into the west.

These three bright stars are an example of stellar variety:

– At bottom is Altair in Aquila the eagle. It’s a white main-sequence star 17 light years away, fairly nearby by stellar standards. Leslie Nielson and his crew went to Altair in the 1950s movie Forbidden Planet.

– At top right is Vega, in Lyra the harp, a hotter and more luminous blue-white star than Altair, making it appear brighter than Altair, despite Vega being farther away, at 25 light years distant. Jodi Foster went to Vega in the movie Contact.

– But the third member of the Triangle, Deneb, at top left, is an extreme star. It appears a little fainter than Vega, but looks can be deceiving. Deneb is actually a luminous supergiant star, putting out 54,000 times the energy of our Sun. Deneb is about 1,400 light years away and yet, due to its fierce output of light, appears almost as bright as Vega. Light from Deneb left that star in the 6th century. I don’t know of any movie heroes who went to Deneb. The name means “tail of the Swan,” hardly a romantic destination for space-faring adventurers.

Look toward the Summer Triangle and you are looking down the spiral arm of the Milky Way that we live in. The stars of that arm appear as a packed stellar cloud running through Cygnus the swan, the constellation that contains Deneb.

I took this shot Saturday night, from home, on what turned out to be a very clear night, once some clouds got out of the way in the early evening. This is a 4-image stack of 8-minute exposures, at f/4 with the 35mm Canon lens, a favourite of mine, on the Canon 5D MkII at ISO 800. I added in exposures taken through a soft-focus filter to give the added glows around the stars to help make the bright stars and their colours more visible.

— Alan, September 25, 2011 / Image © 2011 Alan Dyer

The Comet and the Cluster


This was the scene Monday night and into Tuesday morning, August 1/2, as a relatively new comet to our skies passed a bright globular cluster known as M15 in Pegasus. The comet is Comet Garradd, or more formally C/2009 P1. Here it glows with the characteristic cyan tint of many comets and sports a stubby fan-shaped tail.

As comets move across the sky they often appear near prominent deep-sky objects for a night or two before moving on. Comet Garradd has a number of such encounters coming up: with the globular cluster M71 on August 26, and then near the neat Coathanger cluster September 1 through 3.

Comet Garradd can be spotted now from a dark site in big astronomy binoculars and is a fine sight in a telescope. However, it is well below the threshold of naked-eye brightness and is expected to remain so as it moves high across the summer sky from east to west and then into the western evening sky in late autumn. It is certainly well-placed for viewing, but only comet aficionados are likely to pay much attention to it. Plus astrophotographers taking advantage of photo ops like this one.

— Alan, August 2, 2011 / Image © 2011 Alan Dyer


The Glowing Heart of Cygnus


Look straight up on a summer night in the northern hemisphere and you are looking into this region of sky. This is the centre — the heart — of Cygnus the swan, marked here by the bright star called Sadr, or Gamma Cygni.

While the star is easily visible to the unaided eye, the glowing clouds of gas surrounding it are not. Only long exposure images reveal the amazing swirls of nebulosity in the middle of Cygnus.

The main cloud at left, split by a dark lane of dust, is catalogued as IC 1318. The little crescent-shaped nebula at right is NGC 6888, or more appropriately, the Crescent Nebula. It formed when a hot giant star blew off its outer layers, to add to the general melee of hydrogen and other elements. But note the little blue reflection nebulas at top left. Oddly out of place!

New stars are forming in this region, located about 1500 light years away down the Cygnus arm that we live in, in the Milky Way Galaxy.

This field can be framed nicely by binoculars or a low-power telescope, but only the brightest bits of this nebulosity will show up in the eyepiece as grey ghosts, and then only with the aid of a specialized nebula filter.

I took this shot on Saturday night, July 30, 2011 with the Borg 77mm f/4 astrograph lens and Canon 5D MkII camera. Other stats are similar to the previous blog post. It’s certainly my best shot of this area of sky.

— Alan, August 1, 2011 / Image © 2011 Alan Dyer

 

The Eagle and the Swan


Though they are truly “nebulous,” these clouds of interstellar gas carry fanciful names — our human attempt to make sense of the vast chaotic forms that pervade deep space.

Above is the Eagle Nebula, a.k.a. Messier 16. Below lies the Swan Nebula, a.k.a. Messier 17. Through a telescope to the eye these nebulas do take on the imagined shape of interstellar birds flying along the Milky Way. But long exposure images like this bring out far more than the eye can see. The entire field, here about the width of what high-power binoculars take in, is filled with swirls of hydrogen gas, glowing in its characteristic red colour.

The Eagle Nebula lies in the constellation of Serpens the serpent, while the Swan Nebula lies just over the border in Sagittarius the archer.

I took this shot Saturday night, July 30, 2011, on one the few perfect nights of observing we get here in Canada — the night was warm, dry, with little wind and no mosquitoes. I could venture out with just a sweater on for a bit of warmth. A far cry from the parkas and down-filled boots normally needed.

This field is a first for me from Canada. I’ve shot it from Australia and Chile, where these objects lie overhead, never from home in Alberta at a latitude of 51° North. But the night was so transparent, the field was worth going after, despite it being low on the southern horizon and at its best for no more than an hour after it got dark.

To shoot the field, I used the wonderful little Borg 77mm f/4 astrographic refractor, effectively a 300mm telephoto lens but far sharper and flatter than most telephotos made for sports and wildlife. The camera was the Canon 5D MkII, a filter-modified version that has a special filter for passing more of the deep red colour of hydrogen. But the real difference here was the use of a filter at the focus of the telescope that further isolated the red wavelengths and blocked other colours that might have otherwise fogged the image, especially from a field so low on the horizon. It worked great, though does tend to render the whole field on the red side.

— Alan, July 31, 2011 / Image © 2011 Alan Dyer

 

A Window in the Stars


In this part of the sky the Milky Way takes on a surprising palette of hues. And it’s all due to dust.

The centrepiece of this shot is a bright star cloud in Sagittarius called, well, the Sagittarius Star Cloud! But not the Large one. This is the Small Sagittarius Star Cloud, a.k.a. Messier 24, a mass of stars with a single black eye. The dark spot, called Barnard 92, is a dense and opaque cloud of dust. Stardust — clouds of carbon soot blown out by aging stars — weaves all through this scene, creating the dark canyons winding through the stars. Obscuring dust also dims much of the background stars and discolours most of this part of the Milky Way a yellowish brown. It’s the same effect that dims the setting Sun a deep orange or red, as its light shines through haze and dust in the sky.

But here, the Star Cloud looks bluish and “cleaner.” That part of the Milky Way has less dust in front of it. And yet it is much farther away than the yellow dusty starfields around it. When we look toward the Small Sagittarius Star Cloud we are looking through a dust-free window, allowing us to see unencumbered right past our Galaxy’s nearby Sagittarius-Carina spiral arm to glimpse a dense part of the more distant Norma Arm, an inner spiral arm of our Milky Way Galaxy about 12,000 to 16,000 light years away.

To the lower right of M24 is M23, a rich cluster of stars 2,000 light years away, nearby by galactic standards, and so sits suspended in front of the fainter star background. The pinkish nebula at top is Messier 17, the Swan Nebula.

I took this shot May 2 from Chile, using the Canon 7D and 135 lens, for a stack of six 2-minute exposures.

— Alan, June 7, 2011 / Image © 2011 Alan Dyer

 

 

Rose of the Southern Sky


It’s been a month since my last post, a month with no new astrophotos from home. But I’ve got a backlog of RAW files to work through from the Chile trip a month ago. Here’s a new image from that shooting expedition. It’s of an area of the southern sky that lends itself to every focal length and framing variation — you can’t go wrong with the Carina Nebula!

This wonderful nebula in the deep-south Milky Way rewards any astrophotographer. For this shot I used a 135mm telephoto (Canon’s wonderful f/2 L-series lens) and the Canon 7D camera. The 7D is what I call a “stock” camera, used just as it comes off the dealer shelf. The 7D does a superb job capturing the red nebulosity and its faint outlying bits and pieces. It tends to record these clouds of glowing hydrogen as magenta in tone. By comparison, my other Canon camera is a “filter-modified” 5D MkII. You can see a shot of this same area of sky taken with the 5D MkII a few blogs back under The Best Nebula in the Sky, posted May 6. The 5D MkII’s modification (which replaces the filter in front of the sensor with a new astro-friendly one) allows it to record deep-red wavelengths and picks up more faint nebulosity, registering it more as red in tone. But both images look good and presentable.

This field is rich in objects — not only the main sprawling nebula but nearby star clusters and patches of dark dust clouds. It is one of the finest fields in the sky for binoculars, and this shot approximates the field of view of typical binos. I like to shoot a lot of objects with telephoto lenses — while the main subject is not frame-filling and in your face, it does match (at least in field of view) what you can see in binos, useful for illustrations and observing articles. Of course, the camera picks up  more stuff and colours even your bino-aided eyes can’t see.

This shot is a stack of five 2-minute exposures at f/2.8 with the 135mm telephoto, on the Canon 7D at ISO 1250. I used the little Kenko Sky Memo tracking platform for this, letting it track without any added guiding. It’s tracking was spot on, with nary any star trailing as it followed the target for 20 minutes or so.

— Alan, June 3, 2011 / Image © 2011 Alan Dyer

The Galactic Cathedral


We’re on our last full day in Chile, packing up and sorting out. I’ll finish off my Chile blog series with this parting shot — the entire southern Milky Way from horizon to horizon.

In this view, we’re looking straight up, with the horizon at the edges of the frame of the 15mm fish-eye lens. The glowing starclouds of Sagittarius and Scorpius, seen in close up in the previous blog post, are in the centre of the frame. The Southern Cross is at far right, the Northern Cross at far left.

This scene is a superb way to end a night of southern sky stargazing – just lying back and looking up at the entire panorama of the Galaxy. You really do get the sense that we are indeed living at the edge of the Galaxy, looking off into its bright core, and with its spiral arms wrapping around us.

It’s a galactic cathedral of stars.

– Alan, May 7, 2011 / Image  © 2011 Alan Dyer

The Starfields of Sagittarius and Scorpius


I can’t get enough of this region of sky. I can and do shoot this with every lens I have and with all kinds of framing (horizontally, vertically, or at a rakish angle, like here) and it always looks great.

These are the rich and stunning starfields toward the centre of the Milky Way in Sagittarius (bottom) and Scorpius (at top). Look for the pinkish nebulas dotted along the Milky Way, the bright starclouds, and the dark lanes of interstellar dust. It’s all part of the galactic recycling program that our Milky Way participates in, as stars explode, cast off dust and gas, which then clump into glowing nebulas and form new generations of stars.

I took this shot about 5 a.m. a couple of mornings ago, with this area directly overhead. It’s a stack of six 3-minute exposures with the 35mm lens and Canon 5D MkII camera. I took some shots through a soft focus filter to add the star glows.

– Alan, May 7, 2011 / Image © 2011 Alan Dyer

Springtime Cluster #2: Ancient M67


Poor old M67. Does anyone ever look at this cluster? I tend to ignore it, in favour of its brighter and bigger brother, the Beehive Cluster just to the north. Yet, this smaller cluster ranks with the best of the sky’s open star clusters for richness and brilliance. Only a few showpiece star clusters, like the Beehive and the Pleiades, beat M67.

Located in Cancer, M67 really deserves more respect – even a name! – as it stands out as one of the few prominent deep-sky objects in the otherwise sparse spring sky, at least sparse for bright targets for binoculars or a small telescope. Yes, if you love galaxies, the spring sky is heaven! There are thousands of galaxies to hunt down in spring, but most need a decent-sized telescope to do them justice. By contrast, M67 looks just fine in a small telescope. With a few hundred stars packed into an area the apparent size of the Full Moon this is one rich cluster.

M67 is called that because it is #67 in Charles Messier’s catalog of “things not to be confused as comets.” Messier came across this object in April 1780. Messier ‘s object #67 is one of the few open star clusters not embedded in the Milky Way. Like the Beehive, M67 sits well above the disk of our Galaxy’s spiral arms. We look up out of the plane of the Galaxy to view M67, sitting some 2600 light years away, over four times farther away than its neighbour in Cancer, the Beehive. Thus, M67 looks smaller than the Beehive because it is more distant.

M67 holds the distinction of being one of the oldest star clusters known. It’s been around for over 4 billion years. Its position well above the frenzied traffic jam of our Galaxy’s spiral arms helps M67 stay intact and together, an isolated island of stars in our spring sky.

This image was taken right after the M44 Beehive Cluster shot featured in my previous blog post, using the same gear. So the image scale is the same. You can see how much smaller M67 appears than M44. Because M67 was beginning to sink into the west when I took this, I bumped the camera up to ISO 1600 and used shorter 3 minute exposures and stacked five of them to smooth out noise. The telescope was the little 92mm TMB apo riding on the Astro-Physics 600E mount and flawlessly autoguided with the Santa Barbara Instruments SG-4 autoguider. I really love the SG-4 — just press one button and it’s guiding. True “Push Here Dummy” guiding!

— Alan Dyer, April 2011 / Image © 2011 Alan Dyer

The Neglected Small Magellanic Cloud


It sits not far away in the deep southern sky from its larger counterpart, but it must feel rather inferior and sadly neglected. Pity as this object does have lots to offer.

This is the Small Magellanic Cloud, a satellite galaxy to the Milky Way and a companion to the Large Magellanic Cloud — each is named for Ferdinand Magellan who noted them on his pioneering circumnavigation voyage of the world in the 16th century. The Small Cloud doesn’t contain the number and complexity of nebulas and clusters as does its larger brother, but it does have some lovely offerings, like the complex of cyan-coloured nebulas and related clusters at top.

However, the notable sights in this area of sky aren’t actually part of the SMC. The two globular clusters in the field lie much closer to us. NGC 362 is a nice globular at top, but it pales in comparison (every such object does) next to the amazing object known as 47 Tucanae, or NGC 104, the huge globular cluster at right. It is a wonderful sight in any telescope.

This is a stack of five 7-minute exposures with the Borg 77mm f/4 astrograph and Canon 5D MkII at ISO 800. I took this on my astrophoto trip to Australia in December 2010, a season when this object is ideally placed for viewing. Most times of the year, the SMC is dragging close to the horizon and lost in the murk, as least for shooting. That’s another reason the poor old SMC gets no respect!

— Alan, December 2010 / Image © 2010 Alan Dyer

The Wonder-filled Large Magellanic Cloud


It occupies only a binocular field or two in the sky but … Wow! What a field it is! This is one of the objects that makes a trip to the southern hemisphere for astronomy worth the trek alone. This satellite galaxy of our Milky Way is visible only from south of the equator. It contains so many clusters and nebulas, many in the same telescope field, that just sorting out what you are looking at takes a good star atlas (most don’t plot this region well). This is one of my best shots of the “LMC,” taken on my December Oz trip. It is with the Borg 77mm f/4 astrographic lens/telescope and the filter-modified Canon 5D MkII, that picks up much more red nebulosity (that emits deep red wavelengths) that stock cameras don’t record well.

Even so, I’m always amazed at how so many nebulas in the LMC, and in its smaller counterpart, the nearby Small Magellanic Cloud, record as magenta or cyan, rather than deep red. The most prominent object is the Tarantula Nebula at left of centre. It is an amazing sight in any telescope, especially with a nebula filter.

This is a stack of five 7-minute exposures at ISO 800, with the scope on the AP 400 mount and guided with the SG-4 autoguider. This is a single image, framed to take in all the best stuff of the LMC. But to really get it all in with any detail requires a multi-panel mosaic. I’ve done those on previous trips and was hoping to re-do one on this last trip, with the better, sharper camera, the 5D MkII, and with the LMC higher in the sky than on earlier trips. But the lack of clear nights curtailed my plans.

But I’m happy with this one. Nice and sharp and with oodles of nebulosity. But one can never exhaust what this object has to offer, both for imaging and for just looking with the eyepiece. So there’s always next time!

– Alan, December 2010 / Image © 2010 Alan Dyer