Tracks of the Geosats


This short video, below, captures time-lapses of the trails of geostationary satellites through southern Orion. It demonstrates the “crowded sky” we now have above us. 

If you have tried photographing the Orion Nebula and Sword of Orion area with long tracked exposures you have no doubt seen these trails in your photos. Here I shot to purposely capture them in a time-lapse, for demonstration purposes. 

Please note, these are not Starlink satellites. So do not blame Elon Musk for these! 

These are the much more established geostationary or “geosynchronous” satellites that orbit 35,785 kilometres above Earth and so take 24 hours to orbit the planet. As such they remain apparently motionless over the same spot on Earth, allowing fixed dish antennas to aim at them.

(For more about geosats see the Wikipedia page.)

So why are they moving here?

The camera is on a mount that is tracking the sky as it turns from east to west, so the stars are staying still. What would normally be satellites fixed in one spot in the sky (after all, they are called “geostationary” for a reason) instead trail into short streaks traveling from west to east (right to left) in the frame. But in reality, it is the stars that are in motion behind the satellites. 

The region of sky in Orion below the Orion Nebula (the object at top) lies south of the line that bisects the sky into northern and southern halves called the “celestial equator.” Most geostationary satellites also orbit in Earth’s equatorial plane and so appear along a belt near the celestial equator in the sky. 

This chart from SkySafari shows the belt of geosats through southern Orion with the satellites identified. The green box is the field of view of the telescope (shown below) that I used to take the time-lapses.

In this video, however, they appear about 5° to 7° south of the celestial equator (which runs through the famous Belt of Orion off frame at top). That’s because I live north of the equator of the Earth, at a latitude of 51° north. So parallax makes the geosat belt appears south of the celestial equator in my sky. From a site in the southern hemisphere the geosat belt would appear north of the celestial equator.

You’ll notice some satellites travelling diagonally — they are not geosats. You’ll also see some flashing or pulsing satellites — they are likely tumbling objects, perhaps spent rocket boosters.

The satellites are visible because they are high enough to reflect sunlight even in the middle of the night, as the sequences each end about 11:30 to midnight local time.

But in this video the satellites are not flaring — this is their normal brightness. During flare season around the two equinoxes geosats can become bright enough to be seen with the unaided eye. For a video of that phenomenon see my video shot in October 2020, below. 


TECH DETAILS FOR “TRACKS OF THE GEOSATS” VIDEO:

The video at top contains time-lapses shot on two nights: January 18 and 20, 2021. Both are made from hundreds of frames taken through a William Optics RedCat astrograph at f/5 with a 250mm focal length. The field of view is 8° by 5.5°. 

The William Optics RedCat 51mm f/5 astrographic refactor.

Each exposure is 30 seconds long, taken at a one second interval. The camera was a Canon 6D MkII at ISO 3200 on January 18 and ISO 1600 on January 20 in the brighter moonlight that night. 

In the first sequence from January 18 the equatorial mount, an Astro-Physics Mach1, is left to track on its own and is unguided. So the stars wobble back and forth slightly due to periodic error in the mount. The field also drifts north due to slight misalignment on the pole. Clouds pass through the field during the shoot. 

In the second clip from January 20, taken with a quarter Moon lighting the sky, the mount was autoguided, using an MGEN3 auto-guider. So the stars remained better fixed over the 5.5 hours of shooting. A slight glitch appears near the end where I swapped camera batteries, and the camera turned ever so slightly causing the stars to enlarge a bit for a moment. 

LRTimelapse at work processing the second sequence, deflickering some of the oddly exposed frames.

The frames were processed in Adobe Camera Raw and LRTimelapse

TimeLapse DeFlicker at work assembling the video, showing its All Frames + Lighten blend mode for the Accumulating version of clip #2.

I then assembled exported JPGs with TimeLapseDeFlicker, using a 3-frame Lighten blend mode to lengthen the trails. The final version was assembled with TLDF’s All Frames mode (shown above) where every frame gets stacked for an accumulated total, to show the busy sky traffic! 

Thanks! 

— Alan, © 2021 / AmazingSky.com 

How to Photograph the Great Conjunction


On December 21 we have a chance to see and shoot a celestial event that no one has seen since the year 1226. 

As Jupiter and Saturn each orbit the Sun, Jupiter catches up to slower moving Saturn and passes it every 20 years. For a few days the two giant planets appear close together in our sky. The last time this happened was in 2000, but with the planets too close to the Sun to see. 

Back on February 18, 1961 the two planets appeared within 14 arc minutes or 0.23° (degrees) of each other low in the dawn sky. 

But on December 21 they will pass each other only 6 arc minutes apart. To find a conjunction that close and visible in a darkened sky you have to go all the way back to March 5, 1226 when Jupiter passed only 3 arc minutes above Saturn at dawn. Thus the media headlines of a “Christmas Star” no one has seen for 800 years! 

Photographing the conjunction will be a challenge precisely because the planets will be so close to each other. Here are several methods I can suggest, in order of increasing complexity and demands for specialized gear. 


Easy — Shooting Nightscapes with Wide Lenses

This shows the field of view of various lenses on full-frame cameras (red outlines) and a 200mm lens with 1.4x tele-extender on a cropped frame camera (blue outline). The date is December 17 when the waxing crescent Moon also appears near the planet pair for a bonus element in a nightscape image.

Conjunctions of planets in the dusk or dawn twilight are usually easy to capture. Use a wide-angle (24mm) to short telephoto (85mm) lens to frame the scene and exposures of no more than a few seconds at ISO 200 to 400 with the lens at f/2.8 to f/4. 

The sky and horizon might be bright enough to allow a camera’s autoexposure and autofocus systems to work. 

Indeed, in the evenings leading up to and following the closest approach date of December 21 that’s a good method to use. Capture the planet pair over a scenic landscape or urban skyline to place them in context. 

For most locations the planets will appear no higher than about 15° to 20° above the southwestern horizon as it gets dark enough to see and shoot them, at about 5 p.m. local time. A 50mm lens on a full-frame camera (or a 35mm lens on a cropped frame camera) will frame the scene well. 

This was Jupiter and Saturn on December 3, 2020 from the Elbow Falls area on the Elbow River in the Kananaskis Country southwest of Calgary. This is a blend of 4 untracked images for the dark ground, stacked to smooth noise, for 30 seconds each, and one untracked image for the bright sky for 15 seconds to preserve colours and highlights, all with the 24mm Sigma lens and Canon EOS Ra at ISO 200.

NIGHTSCAPE TIP — Use planetarium software such as Stellarium (free), SkySafari, or StarryNight (what I used here) to simulate the framing with your lens and camera. Use that software to determine where the planets will be in azimuth, then use a photo planning app such as PhotoPills or The Photographer’s Ephemeris to plan where to be to place the planets over the scene you want at that azimuth (they’ll be at about 220° to 230° — in the southwest — for northern latitude sites). 

My ebook linked to at right has pages of tips and techniques for shooting nightscapes and time-lapses. 

This was Jupiter and Saturn on December 10, 2020 from Red Deer River valley, north of Drumheller, Alberta. This is a blend of 4 images for the dark ground, stacked to smooth noise, for 20 seconds each at f/5.6, and a single image for the sky for 5 seconds at f/2.8, all with the 35mm Canon lens and Canon EOS Ra at ISO 400. All untracked.

Harder — Shooting With Longer Lenses

The planet pair will sink lower and closer to the horizon, to set about 7:00 to 7:30 p.m. local time each night. 

As the sky darkens and the planet altitude decreases you can switch to ever-longer lenses to zoom in on the scene and still frame the planets above a carefully-chosen horizon, assuming you have very clear skies free of haze and cloud. 

For example, by 6 p.m. they will be low enough to allow a 135mm telephoto to frame the planets and still have the horizon in the frame. Using a longer lens has the benefit or resolving the two planets better, showing them as two distinct objects, which will become more of a challenge the closer you are to December 21. 

On December 21 wide-angle and even short telephoto lenses will likely show the two planets as an unresolved point of light, no brighter than Jupiter on its own.

On closest approach day the planets will be so close that using a wide-angle or even a normal lens might only show them as an unresolved blob of light. You’ll need more focal length to split the planets well into two objects. 

However, using longer focal lengths introduces a challenge — the motion of the sky will cause the planets to trail during long exposures, turning them from points into streaks. That trailing will get more noticeable more quickly the longer the lens you use. 

A rule-of-thumb says the longest exposure you can employ before trailing becomes apparent is 500 / the focal length of the lens. So for a 200mm lens, maximum exposure is 500 / 200 = 2.5 seconds. 

To be conservative, a “300 Rule” might be better, restricting exposures with a 200mm telephoto to 300 / 200 = 1.5 seconds. Now, 1.5 seconds might be long enough for the scene, especially if you use a fast lens wide open at f/2.8 or f/2 and a faster ISO such as 400 or 800. 

This shows the motion of Jupiter relative to Saturn from December 17 to 25, with the outer frame representing the field of view of a 200mm lens and 1.4x tele-extender on a cropped frame camera. The smaller frame shows the field of a telescope with an effective focal length of 1,200mm.

TELEPHOTO TIP — Be sure to focus carefully using Live View to manually focus on a magnified image of the planets. And refocus through an evening of shooting. While people fuss about getting the one “correct” exposure, it is poor focus that ruins more astrophotos. 


Even More Demanding — Tracking Longer Lenses 

This one popular sky tracker, the iOptron SkyGuider Pro, here with a telephoto lens. It and other trackers such as the Sky-Watcher Star Adventurer seen in the opening image, can be used with lenses and telescopes up to about 300mm focal length, if they are balanced well. Even longer lenses might work for the short exposures needed for the planets, but vibration and wind can blur images.

However, longer exposures might be needed later in the evening when the sky is darker, to set the planets into a starry background. After December 17 we will have a waxing Moon in the evening sky to light the sky and foreground, so the sky will not be dark, even from a rural site. 

Even so, to ensure untrailed images with long telephotos — and certainly with telescopes — you will need to employ a sky tracker, a device to automatically turn the camera to follow the sky. If you don’t have one, it’s probably too late to get one and learn how to use it! But if you have one, here’s a great opportunity to put it to use. 

Polar align it (you’ll have to wait for it to get dark enough to see the North Star) and then use it to take telephoto close-up images of the planets with exposure times that can now be as long as you like, though they likely won’t need to be more than 10 to 20 seconds. 

You can now also use a slower ISO speed for less noise. 

TRACKER TIP — Use a telephoto to frame just the planets, or include some foreground content such as a hilltop, if it can be made to fit in the frame. Keep in mind that the foreground will now blur from the tracking, which might not be an issue. If it is, take exposures of the foreground with the tracker motor off, to blend in later in processing. 


The Most Difficult Method — Using a Telescope

An alt-azimuth mounted GoTo scope like this Celestron SE6 can work for short exposures of the planets, provided it is aligned and is tracking properly. Good focus will be critical.

Capturing the rare sight of the planets as two distinct disks (not just dots of light) accompanied by their moons, all together in the same frame, is possible anytime between now and the end of the year. 

But … resolving the disks of the planets takes focal length — a lot of focal length! And that means using a telescope on a mount that can track the stars. 

While a sky tracker might work, they are not designed to handle long and heavy lenses and telescopes. You’d need a telescope on a solid mount, though it could be a “GoTo” telescope on an alt-azimuth mount. Such a mount, while normally not suited for long-exposure deep-sky imaging, will be fine for the short exposures needed for the planets.

You will need to attach your camera to the telescope using a camera adapter, so the scope becomes the lens. If you have never done this, to shoot closeups of the Moon for example, and don’t have the right adapters and T-rings, then this isn’t the time to learn how to do it.

A simulation of the view with a 1,200mm focal length telescope on December 21. Even with such a focal length the planet disks still appear small.

TELESCOPE TIP — As an alternative, it might be possible to shoot the planets using a phone camera clamped to the low-power eyepiece of a telescope, but focusing and setting the exposure can be tough. It might not be worth the fuss in the brief time you have in twilight, perhaps on the one clear night you get! Just use your telescope to look and enjoy the view! 

But if you have experience shooting the Moon through your telescope with your DSLR or mirrorless camera, then you should be all set, as the gear and techniques to shoot the planets are the same. 

This is the setup I might use for a portable rig best for a last-minute chase to clear skies. It’s a Sky-Watcher EQM-35 mount with a 105mm apo refractor (the long-discontinued Astro-Physics Traveler), and here with a 2x Barlow to double the effective focal length to 1,200mm.

However, once again the challenge is just how close the planets are going to get to each other. Even a telescope with a focal length of 1200mm (typical for a small scope) still gives a field of view 1° wide using a cropped frame camera. That’s 60 arc minutes, ten times the 6 arc minute separation of Jupiter and Saturn on December 21! 

TELESCOPE TIP — Use a 2x or 3x Barlow lens if needed to increase the effective focal length of the scope. Beware that introducing a Barlow into the light path usually requires racking the focus out and/or adding extension tubes to reach focus. Test your configuration as soon as possible to make sure you can focus it. 

TELESCOPE TIP — With such long focal lengths shoot lots of exposures. Some will be sharper than others. 

TELESCOPE TIP — But be sure to focus precisely, and refocus over the hour or so you might be shooting, as changing temperatures will shift the focus. You can’t fix bad focus! 

Jupiter and Saturn in the same telescope field on December 5, 2020. Some of the moons are visible in this exposure taken in twilight before the planets got too low in the southwest. This is a single exposure with a 130mm Astro-Physics apo refractor at f/6 (so 780mm focal length) for 4 seconds at ISO 200 with the Canon 6D MkII. The disks of the planets are overexposed to bring out the moons.

Short exposures under one second might be needed to keep the planet disks from overexposing. Capturing the moons of Jupiter (it has four bright moons) and Saturn (it has two, Titan and Rhea, that are bright) will require exposures of several seconds. Going even longer will pick up background stars.

Or … with DSLRs and mirrorless cameras, try shooting HD or 4K movies. They will likely demand a high and noisy ISO, but might capture the view more like you saw and remember it. 

FINAL TIP — Whatever combination of gear you decide to use, test it! Don’t wait until December 21 to see if it works, nor ask me if I think such-and-such a mount, telescope or technique will work. Test for yourself to find out.

Jupiter and Saturn taken in the deep twilight on December 3, 2020 from the Allen Bill flats area on the Elbow River in the Kananaskis Country southwest of Calgary, Alberta. This is a blend of 4 untracked images for the dark ground, stacked to smooth noise, for 2 minutes each at ISO 400, and two tracked images for the sky (and untrailed stars) for 30 seconds each at ISO 400, all with the 35mm Canon lens at f/2.8 and Canon EOS Ra. The tracker was the Sky-Watcher Star Adventurer 2i.

Don’t Fret or Compete. Enjoy! 

The finest images will come from experienced planetary imagers using high-frame-rate video cameras to shoot movies, from which software extracts and stacks the sharpest frames. Again, if you have no experience with doing that (I don’t!), this is not the time to learn! 

And even the pros will have a tough time getting sharp images due to the planets’ low altitude, even from the southern hemisphere, where some pro imagers have big telescopes at their disposal, to get images no one else in the world can compete with!

In short, use the gear you have and techniques you know to capture this unique event as best you can. And if stuff fails, just enjoy the view! 

Jupiter and Saturn taken December 3, 2020 from the Allen Bill flats area on the Elbow River in the Kananaskis Country southwest of Calgary, Alberta. This is a blend of 4 untracked images for the dark ground, stacked to smooth noise, for 2 minutes each at ISO 400, and two tracked images for the sky for 30 seconds at ISO 1600, all with the 35mm Canon lens at f/2.8 and Canon EOS Ra. The tracker was the Sky-Watcher Star Adventurer 2i.

If you miss closest approach day due to cloud, don’t worry. 

Even when shooting with telephoto lenses the photo ops will be better in the week leading up to and following December 21, when the greater separation of the planets will make it easier to capture a dramatic image of the strikingly close pairing of planets over an Earthly scene. 

Clear skies! 

— Alan, © 2020 AmazingSky.com 

The Rising of the Harvest Moon


On two clear evenings the Harvest Moon rose red and and large over the Alberta prairie.

I present a short music video (linked to below) of time-lapse sequences of the Harvest Moon of 2020 rising. I shot the sequences through a small telescope to zoom in on the Moon’s disk as it rose over the flat horizon of the prairie near where I live. I love being able to see the horizon!

Note the effects of atmospheric refraction squishing the Moon’s disk close to the horizon. The Moon becomes more normal and spherical as it rose higher.

People sometimes think the refraction effect is responsible for making the Full Moon appear large on the horizon, but the atmosphere has nothing to do with it. The effect is strictly an optical illusion. The Moon is no bigger on the horizon than when it is higher in the sky.

The photo below shows a composite of images taken September 30, 2020.

The rising of the nearly Full Moon, the Harvest Moon of 2020, on September 30, from a site near home in Alberta, looking just south of due east this night. Refraction distorts the disk and atmospheric absorption reddens the disk toward the horizon. This is a multiple exposure composite of 6 images with the Canon 6D MkII through the 80mm A&M apo refractor at f/6 without field flattener. Taken as part of a time-lapse sequence with images every 2 seconds. The frames for this blend were taken 2 minutes apart, so selected from every 60 frames out of the sequence. All were at 1/8 second at ISO 100. Images stacked in Photoshop and blended with Lighten mode. The ground comes from the first image.

Note in the image below, from October 1, how much redder the Moon appears. That’s the effect of atmospheric absorption, in this case from dust and smoke in the air dimming and reddening the Moon (the same happens to the rising or setting Sun). At times this evening it looked like the Moon was in a total eclipse.

The Harvest Moon (the Full Moon of October 1, 2020) rising almost due east at the end of a country road in southern Alberta, near home. The horizon was smoky or dusty, so the Moon was very red as it rose, and looking almost like a totally eclipsed Moon. This is a blend of 6 exposures, all 1/2-second with the A&M 80mm f/6 apo refractor (for 480mm focal length) and Canon 6D MkII at ISO 400, taken as part of a 460-frame time-lapse sequence, with shots every 2 seconds. For this composite I choose 6 images at 2-minute intervals, so the Moon rose its own diameter between frames. The ground comes from the first image in the sequence when the lighting was brightest. The Moon rose at 7:35 pm this night, about 30 minutes after sunset. A mild Orton glow effect added to the ground with Luminar 4.

Below is the link to the time-lapse music video on Vimeo. It is in 4K. I used Adobe Camera Raw, Adobe Bridge, and LRTimelapse to process the component images as raw files for the time-lapse sequences, as per tutorials in my Nightscape and Time-Lapse ebook, above.

Thanks for looking! Clear skies!

— Alan / © 2020 www.amazingsky.com

The Great Transit Expedition of 2019


Blog Title

On November 11, I traveled to the near-flung corners of my backyard to observe the rare transit of Mercury across the Sun.

History is replete with tales of astronomers traveling to the far corners of the Earth to watch dark objects pass in front of the Sun — the Moon in eclipses, and Mercury and Venus in transits.

On November 11, to take in the last transit of Mercury until 2032, I had planned a trip to a location more likely to have clear skies in November than at home. A 3-day drive to southern Arizona was the plan.

But to attend to work and priorities at home I cancelled my plans. Instead, I decided to stay home and take my chances with the Alberta weather, perhaps making a run for it a day’s drive away if needed to chase into clear skies.

Transit of Mercury Selfie with Sun

As it turned out, none of that was necessary. The forecast for clear, if cold, skies held true and we could not have had a finer day for the transit. Even the -20° C temperatures were no problem, with no wind, and of course sunshine!

Plus being only steps from home and a warming coffee helped!

As it turned out, the site in Arizona I had booked to stay was clouded out for the entire event. So I was happy with my decision!

For my site in Alberta, as for all of western North America, the Sun rose with the transit in progress. But as soon as the Sun cleared the horizon there was Mercury, as a small, if fuzzy, black dot on the Sun.

Low Sun with Mercury in Transit

As the Sun rose the view became sharper, and was remarkable indeed — of a jet black dot of a tiny planet silhouetted on the Sun.

The Transit of Mercury Across the Sun (10 am MST)

I shot through two telescopes, my 4-inch and 5-inch refractors, both equipped with solar filters of course. I viewed through two other telescopes, for white-light and hydrogen-alpha filtered views.

I was able to follow the transit for three hours, for a little more than half the transit, until Mercury exited the Sun just after 11 a.m. MST. The view below is from moments before Mercury’s exit, or “egress.”

The Transit of Mercury Across the Sun (11 am MST)

I shot still frames every 15 seconds with each of the two cameras and telescopes, for a time-lapse, plus I shot real-time videos.

Mercury at Mid-Transit (November 11, 2019)

At this transit Mercury passed closer to the centre of the Sun’s disk than it will for any other transit in the 21st century, making this event all the more remarkable. That point is recorded above, from a shot taken at 8:19 a.m. MST.

Stacking a selection of the time-lapse frames, ones taken 1-minute intervals, produced this composite of the transit, from just before mid-transit until Mercury’s egress.

Transit of Mercury Composite Across the Sun v2

I assembled all the best images and 4K videos together into a movie, which I narrated live at the telescope as the transit was happening. I hope this provides a sense of what it was like to view this rare event.

The Transit of Mercury from Alan Dyer on Vimeo.

We won’t see another until 2032, but not from North America. The next transit of Mercury viewable from here at home is not until 2049! This was likely my last transit, certainly for a while!

Transit of Mercury Trophy Shot

This was my trophy shot! Bagged the transit!

P.S.: For my video of the previous transit of Mercury in May 2016, see my blog post which includes a similar compilation video.

P.P.S.: And for tech details on the images and videos in this blog, please click through to Vimeo and the video description I have there of cameras, scopes, and settings.

Clear skies!

Alan, November 17, 2019 / © 2019 Alan Dyer / amazingsky.com

 

Top 10 Tips for Practicing for the Eclipse


Total Eclipse from Chile

I present suggestions for how to ensure everything under your control will go well on eclipse day. The secret is: Practice, Practice, Practice!

The techniques I suggest practicing are outlined in my previous blog, Ten Tips for the Solar Eclipse. It’s prerequisite reading.

However, while you can read all about how to shoot the eclipse, nothing beats actually shooting to ensure success. But how do you do that, when there’s only one eclipse?

Here are my “Top 10” suggestions:

Total Eclipse of the Sun from the Atlantic (Nov 3, 2013)
Total eclipse of the Sun, November 3, 2013 as seen from the middle of the Atlantic Ocean, from the Star Flyer sailing ship. I took this with a Canon 5D MkII and 16-35mm lens at 19mm for 1/40s at f/2.8 and ISO 800 on a heavily rolling ship.

Wide-Angle Shots – Shoot a Twilight Scene

The simplest way to shoot the eclipse is to employ a camera with a wide lens running on auto exposure to capture the changing sky colors and scene brightness.

  1. Auto Exposure Check in Twilight

    If you intend to shoot wide-angle shots of the eclipse sky and scene below, with anything from a mobile phone to a DSLR, practice shooting a time-lapse sequence or a movie under twilight lighting. Does your camera expose properly when set to Auto Exposure? If you are using a phone camera, does it have any issues focusing on the sky? How big a file does a movie create? 

 


PRACTICE2-Voyager Alt-Az Mount

With Telephotos and Telescopes – Shoot the Filtered Sun

The toughest techniques involve using long lenses and telescopes to frame the eclipsed Sun up close. They need lots of practice. 

  1. Framing and Focusing

    You’ll need to have your safe and approved solar filter purchased (don’t wait!) that you intend to use over your lens or telescope. With the filter in place, simply practice aiming your lens or telescope at the Sun at midday. It’s not as easy as you think! Then practice using Live View to manually focus on the edge of the Sun or on a sunspot. Can you get consistently sharp images?

 


Partial Solar Eclipse in Cloud #1 (Oct 23, 2014)
The partial eclipse of the Sun, October 23, 2014, shot through thin cloud, but that makes for a more interesting photo than one in a clear sky. Despite the cloud, this was still shot through a Mylar filter, on the front of telescope with 450mm focal length, using the Canon 60Da for 1/25 sec exposure at ISO 100.

  1. Exposure Times

Exposures of the filtered Sun will be the same as during the partial phases, barring cloud or haze, as above, that can lengthen exposure times. Otherwise, only during the thin crescent phases will shutter speeds need to be 2 to 3 stops (or EV steps) longer than for a normal Sun.

 


PRACTICE4-Kendrick and Seymour Filters
Solar filters that clamp around the front of lenses are easier to remove than ones that screw onto lenses. They will bind and get stuck!

  1. Filter Removal

With the camera aimed away from the Sun (very important!), perhaps at a distant landscape feature, practice removing the filter quickly. Can you do it without jarring the camera and bumping it off target? Perhaps try this on the Moon at night as well, as it’s important to also test this with the camera and tripod aimed up high.

 


PRACTICE5-Nikon Screens on 80mm
Articulated LCD screens are a great aid for framing and viewing the eclipse in Live View when the camera is aimed up high, as it will be!

  1. Ease of Use

With the Sun up high at midday (as it will be during the eclipse from most sites), check that you can still look through, focus, and operate the camera easily. Can you read screens in the bright daylight? What about once it gets darker, as in twilight, which is how dark it will get during totality.

 


PRACTICE6-Sun Motion Composite
The east-to-west motion of the sky will carry the Sun its own diameter across the frame during totality, making consistent framing an issue with very long lenses and telescopes.

  1. Sun Motion

If you are using an untracked tripod, check how much the Sun moves across your camera frame during several minutes. For videos you might make use of that motion. For still shots, you’ll want to ensure the Sun doesn’t move too far off center.

 


PRACTICE7-HEQ5 with 80mm Mount N
An equatorial mount like this is great but needs to be at least roughly polar aligned to be useful.

  1. Aligning Tracking Mounts

If you plan to use a motorized equatorial mount capable of tracking the sky, “Plan A” might be to set it up the night before so it can be precisely polar aligned. But the reality is that you might need to move on eclipse morning. To prepare for that prospect, practice roughly polar aligning your mount during the day to see how accurate its tracking is over several minutes. Do that by leveling the mount, setting it to your site’s latitude, and aiming the polar axis as close as you can to due and true north. You don’t need precise polar alignment to gain the benefits of a tracking mount – it keeps the Sun centered – for the few minutes of totality.

 


The March Mini-Moon
The Full Moon is the same brightness as the Sun’s inner corona.

Telephotos and Telescopes – Shoot Full Moon Closeups 

  1. Exposure Check

Shoot the Full Moon around July 8 or August 7. If you intend to use Auto Exposure during totality, check how well it works on the Full Moon. It’s the same brightness as the inner corona of the Sun, though the Moon occupies a larger portion of the frame and covers more metering sensor points. This is another chance to check your focusing skill.

 


Impending Occultation of Beta Capricorni
The crescent Moon has a huge range in brightness and serves as a good test object. Remember, the Moon is the same size as the Sun. That’s why we get eclipses!

Telescopes and Telescopes – Shoot Crescent Moon Closeups

  1. Exposure Check

Shoot the waxing crescent moon in the evening sky during the last week of June and again in the last week of July. Again, test Auto Exposure with your camera in still or movie mode (if you intend to shoot video) to see how well the camera behaves on a subject with a large range in brightness. Or step through a range of exposures manually, from short for the bright sunlit crescent, to long for the dark portion of the Moon lit by Earthshine. It’s important to run through your range of settings quickly, just as you would during the two minutes of totality. But not too quickly, as you might introduce vibration. So …

 


PRACTICE10-2006 Libya-Short
Good focus matters for recording the fine prominences and sharp edge of the Moon.

  1. Sharpness Check

In the resulting images, check for blurring from vibration (from you handling the camera), from wind, and from the sky’s east-to-west motion moving the Moon across the frame, during typical exposures of 1 second or less.

 


By practicing, you’ll be much better prepared for the surprises that eclipse day inevitably bring. Always have a less ambitious “Plan B” for shooting the eclipse simply and quickly should a last-minute move be needed.

However, may I recommend …

How to Photograph the Solar Eclipse
My 295-page ebook on photographing the August 21 total eclipse of the Sun is now available. See http://www.amazingsky.com/eclipsebook.html It covers all techniques, for both stills, time-lapses, and video, from basic to advanced, plus a chapter on image processing. And a chapter on What Can Go Wrong?! The web page has all the details on content, and links to order the book from Apple iBooks Store (for the best image quality and navigation) or as a PDF for all other devices and platforms.

For much more detailed advice on shooting options and techniques, and for step-by-step tutorials on processing eclipse images, see my 295-page eBook on the subject, available as an iBook for Apple devices and as a PDF for all computers and tablets.

Check it out at my website page

Thanks and clear skies on August 21!

— Alan, June 24, 2017 / © 2017 Alan Dyer / amazingsky.com

 

Transit of Mercury


Transit of Mercury near Sunrise

On May 9, a last-minute chase into clear skies netted me a view of the rare transit of Mercury across the Sun.

The forecast called for typical transit weather – clear the day before, and clear the day after. But the day of the transit of Mercury? Hopeless at home in Alberta, unless I chanced the prospects of some clearing forecast for central Alberta.

As the satellite image below, for 8:30 a.m. MDT on May 9, shows, that clearing did materialize. But I headed west, as far west as I needed to go to be assured of clear skies – to central BC. Kamloops in fact.

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I stayed at the Alpine Motel, got a great room as the end, and set up in the parking lot away from traffic. Not the most photogenic of observing sites, but I was happy! I had my clear skies!

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I set up two telescopes, above: a 130mm refractor to shoot through, and an 80mm refractor to look through. Both with dense solar filters!

Both worked great. However, low cloud prevented me seeing the Sun as soon as it cleared the eastern hills. So this was my first good look, below, at the transit as the Sun rose above the clouds.

Transit of Mercury near Sunrise
The May 9, 2016 transit of Mercury taken about half an hour after sunrise, as the Sun emerged from low horizon cloud. Taken from Kamloops, British Columbia, where the transit was well underway at sunrise. Mercury appears as the circular dot at lower left, with a sunpot group above centre. I shot this with the 130mm Astro-Physics refractor at f/6 prime focus with the Canon 60Da camera at ISO 100. Shot through a Kendrick white light solar filter. The low atltitude added much of the yellow colouration.

There it was – the fabled “little black spot on the Sun today.” Mercury is the dot at lower left, with a sunspot group at upper right. This was the first transit of Mercury since November 8, 2006. We see only about 13 Mercury transits a century, so in a lifetime of stargazing (the Sun is a star!) even the most avid amateur astronomer might see only a handful. This was only my third transit of Mercury.

Transit of Mercury in Clouds
The May 9, 2016 transit of Mercury taken about 45 minutes after sunrise, as the Sun emerged from low horizon cloud. I shot this with the 130mm Astro-Physics refractor at f/6 prime focus with the Canon 60Da camera at ISO 100. Shot through a Kendrick white light solar filter.

This was the view, above, a little later, as the Sun entered more assuredly clear skies. From about 7 a.m. PDT on, the Sun was in the clear most of the morning, with just occasional puffy clouds intervening now and then.

I shot still images every 30 seconds, to eventually turn into a time-lapse movie (after a ton of work hand registering hundreds of frames!).

But for now, I’ll be content with this composite of 40 frames, below, taken at 7-minute intervals. It shows the progress of Mercury across the Sun over the last 4.5 hours or so of the event, until egress at 11:38 a.m. PDT.

This motion is due to Mercury’s movement around the Sun. A transit is one of the few times you can easily see a planet actually orbiting the Sun.

Transit of Mercury (May 9, 2016) Composite with Arrow
For all images I used the 130mm f/6 Astro-Physics refractor with a 2X Barlow for an effective focal length of 1560mm and the Canon 60Da camera (at ISO 100) to yield an image size with the Sun just filling the frame. Exposures were 1/250th second through a Kendrick white light Mylar filter. Yellow colouration of the solar disk added in processing.

In this composite, the disks of Mercury are not all perfect dots. The wobbly seeing conditions distorted the images from frame to frame. But I used the actual images taken at that moment, rather than clone some perfect image across the disk to simulate the path.

To wrap up, here’s Mercury Transit: The Movie! I shot several HD and zoomed-in “crop mode” movies at the beginning of the transit and again at the final egress. Commentary is from me talking live into the camera mic as I was shooting the clips. Background noise is courtesy Pacific Drive and the Trans-Canada Highway!

Enjoy, and do enlarge to HD and full-screen for the best look.

 

The next transit of Mercury is November 11, 2019. If you are hoping for a transit of Venus, good luck. The next is not until December 10, 2117!

– Alan, May 15, 2016 / © 2016 Alan Dyer / www.amazingsky.com

 

Relaunching Stargazing in Barbados


Observatory Viewing in Barbados (Nov 16, 2013) #1

Barbados is soon to have a new state-of-the-art public observatory for promoting astronomy.

On Saturday night, November 16, I was fortunate and privileged to be the guest speaker at the first event at the newly refurbished Harry Bayley Observatory in Bridgetown, Barbados. A grant from an educational foundation in the UK has allowed the Barbados Astronomical Society to renew the aging 50-year-old facility with a fresh new interior, and all the high-tech fittings of a modern public observatory.

A new dome was lifted into place on top of the 3-storey structure earlier in the week, and the painting and interior finishing was completed just a day or two before my talk, in time for a public RSVP event Saturday night.

Observatory Interior Panorama #1

I gave a talk on The Amazing Sky, showing images and movies from the November 3 total eclipse, among many other photos of the sights anyone can see in the day and night sky. I gave the same talk twice, to two packed houses of 40 people per session in the main floor meeting room/lecture hall. A wonderful spread of local food and drink was served upstairs.

Lots of work remains to complete the refurbishment but the facility was in good enough shape to host a public event. The official opening is in January.

Observatory Viewing in Barbados (Nov 16, 2013) #3

A new Meade 16-inch telescope on a Software Bisque MX2 mount is on its way for installation later this year, equipped with the latest robotic control and digital cameras for public viewing. A hydrogen-alpha solar telescope will also be part of the arsenal of equipment.

This night, members set up a portable Celestron 8-inch telescope outside for viewing the Moon and Jupiter. In contrast to viewing at home at this time of year, observing from 13° North latitude was in shorts and shirt-sleeves.

It was a terrific evening and I’m pleased to have been part of the relaunching of the Observatory and astronomy activities on the island. Many thanks go to my host on the island, Greg Merrick, for making the evening – and my stay this week – possible.

– Alan, November 17, 2013 / © 2013 Alan Dyer

Aurora at the Observatory


Aurora over Calgary from RAO (May 25, 2013)

A low aurora appears in the city skyglow and bright moonlight at the local observatory. 

After several days of rain, skies cleared beautifully for a Saturday night star party for the public at the local university observatory, the Rothney Astrophysical Observatory, southwest of Calgary.

The evening was capped off by the appearance, as expected, of an auroral arc to the north. Despite the light from the nearly Full Moon and urban sky glow to the north, the aurora managed to compete and put on a show for a few minutes before fading.

RAO Open House (May 25, 2013) #10

RAO Open House (May 25, 2013) #13

About 100 people attended the evening, and were treated to views of Saturn, shining in the south near Spica. Unfortunately, clouds to the west over the mountains never cleared away enough to allow us views, and me photos, of the triple-planet conjunction of Mercury, Venus and Jupiter. Still, a good time was had by all.

– Alan, May 26, 2013 / © 2013 Alan Dyer