The annual Geminid meteor shower peaks under ideal conditions this year, providing a great photo opportunity.
The Geminids is the best meteor shower of the year, under ideal conditions capable of producing rates of 80 to 120 meteors an hour, higher than the more widely observed Perseids in August. And this year conditions are ideal!
The Perseids get better PR because they occur in summer. For most northern observers the Geminids demand greater dedication and warm clothing to withstand the cool, if not bitterly cold night.
A Good Year for Geminids
While the Geminids occur every year, many years are beset by a bright Moon or poor timing. This year conditions couldn’t be better:
• The shower peaks on the night of December 13-14 right at New Moon, so there’s no interference from moonlight at any time on peak night.
• The shower peaks in the early evening of December 13 for North America, about 8 p.m. EST (5 p.m. PST). This produces a richer shower than if it peaked in the daytime hours, as it can in some years.
The two factors make this the best year for the Geminids since 2017 when I shot all the images here.
A composite of the 2017 Geminid meteor shower looking east to the radiant point. This is a stack of 40 images, each a 30-second exposure at f/2.5 with the Rokinon 14mm SP lens and Canon 6D MkII at ISO 6400. The images are the 40 frames with meteors out of 357 taken over 3.25 hours. The ground is a stack of 8 images, mean combined to smooth noise. The background base-image sky is from one exposure. The camera was on a fixed tripod, not tracking the sky. I rotated and moved each image in relation to the base image and around Polaris at upper left, in order to place each meteor at approximately the correct position in relation to the background stars, to preserve the effect of the meteors streaking from the radiant near Castor at centre.
What Settings to Use?
To capture the Geminids, as is true of any meteor shower, you need:
A good DSLR or mirrorless camera set to ISO 1600 to 6400.
A fast, wide-angle lens (14mm to 24mm) set to f/2.8 or wider, perhaps f/2. Slow f/4 to f/.6 kit zooms are not very suitable.
Exposures of 30 to 60 seconds each.
An intervalometer to fire the shutter automatically with no more than 1 second between exposures. As soon as one exposure ends and the shutter closes, the next exposure begins.
Take hundreds of images over as long a time period as you can on peak night.
Use an intervalometer to control the shutter speed, with the camera on Bulb. Set the interval to one second to minimize the time the shutter is closed.
Out of hundreds of images, a dozen or more should contain a meteor! You increase your chances by using:
A high ISO, so the meteor records in the brief second or two it appears.
A wide aperture, to again increase the light-gathering ability of the lens for those fainter meteors.
A wide-angle lens so you capture as much area of sky as possible.
Running two or more cameras aimed at different spots, perhaps to the east and south to maximize sky coverage.
A minimum interval between exposures. Increase the interval to more than a second and you know it’s during that “dark time” when the shutter is closed that the brightest meteor of the night will occur. Keep the shutter open as much as possible.
This sky chart looking east for December 13, 2020 shows the position of the radiant and the constellation of Gemini at about 7 p.m. local time. Orion is just rising in the east.
When to Shoot?
The radiant point of the shower meteors in Gemini rises in the early evening, so you might see some long, slow Earth-grazing meteors early in the night, streaking out of the east.
For Europe the peak of the shower occurs in the middle of the night of December 13/14.
For North America, despite the peak occurring in the early evening hours, meteors will be visible all night and will likely be best after your local midnight.
So wherever you are, start shooting as the night begins and keep shooting for as long as you and your camera can withstand the cold!
A single bright meteor from the Geminid meteor shower of December 2017, dropping toward the horizon in Ursa Major. Gemini itself and the radiant of the shower is at top centre. It is one frame from a 700-frame sequence for stacking and time-lapses. The ground is a mean stack of 8 frames to smooth noise. Exposures were 30 seconds at ISO 6400 with the Rokinon 14mm lens at f/2.5 and Canon 6D MkII.
Where to Go?
To take advantage of the moonless night, get away from urban light pollution to as dark a sky as you can. Preferably, put the major urban skyglow to the west or north.
While from brightly lit locations the very brightest meteors will show up, they are the rarest, so you’d be fortunate to capture one in a night of shooting from a city or town.
From a dark site, you can use longer exposures, wider apertures and higher ISOs to boost your chances of capturing more and fainter meteors. Plus the Milky Way will show up.
The Geminid meteor shower of December 13, 2017 in a view framing the winter Milky Way from Auriga (at top) to Puppis (at bottom) with Gemini itself, the radiant of the shower at left, and Orion at right. The view is looking southeast. This is a composite stack of one base image with the brightest meteor, then 20 other images layered in each with a meteor. The camera was not tracking the sky, so I rotated and moved each of the layered-in frames so that their stars mroe or less aligned with the base layer. The images for this composite were taken over 107 minutes, with 22 images containing meteors picked from 196 images in total over that time. Each exposure was 30 seconds with the Rokinon 14mm SP lens at f/2.5 and Canon 6D MkII at ISO 6400.
Where to Aim?
You can aim a camera any direction, even to the west.
But aiming east to frame the constellation of Gemini (marked by the twin stars Castor and Pollux) will include the radiant point, perhaps capturing the effect of meteors streaking away from that point, especially if you stack multiple images into one composite, as most of my images here are.
The Star Adventurer star tracker, on its optional equatorial wedge to aid precise polar alignment of its motorized rotation axis.
Using a Tracker
Using a star tracker such as the Sky-Watcher Star Adventurer shown here, makes it possible to obtain images with stars that remain untrailed even in 1- or 2-minute exposures. The sky remains framed the same through hours of shooting, making it much easier to align and stack the images for a multi-meteor composite.
A tracked composite showing the 2017 Geminid meteors streaking from the radiant point in Gemini at upper left. This is a stack of 43 exposures, each 1-minute with the 24mm Canon lens at f/2.5 and filter-modified Canon 5D MkII camera at ISO 6400, set fast to pick up the fainter meteors. These were 43 exposures with meteors (some with 2 or 3 per frame) out of 455 taken over 5 hours. The background sky comes from just one of the exposures. All the other frames are masked to show just the meteor.
However, a tracker requires accurate polar alignment of its rotation axis (check its instruction manual to learn how to do this) or else the images will gradually shift out of alignment through a long shoot. Using Photoshop’s Auto-Align feature or specialized stacking programs can bring frames back into registration. But good polar alignment is still necessary.
If you aim east you can frame a tracked set so the first images include the ground. The camera frame will move away from the ground as it tracks the rising sky.
A composite of the 2017 Geminid meteor shower, from the peak night of December 13, with the radiant in Gemini, at top, high overhead. So meteors appear to be raining down to the horizon. This was certainly the visual impression. This is a stack of 24 images, some with 2 or 3 meteors per frame, each a 30-second exposure at f/2.5 with the Rokinon 14mm SP lens and Canon 6D MkII at ISO 6400. The images are the 24 frames with meteors out of 171 taken over 94 minutes. The ground is a stack of 8 images, mean combined to smooth noise. The background base-image sky is from one exposure. The camera was on a fixed tripod, not tracking the sky.
Using a Tripod and Untracked Camera
The simpler method for shooting is to just use a camera (or two!) on a fixed tripod, and keep exposures under about 30 seconds to minimize star trailing. That might mean using a higher ISO than with tracked images, especially with slower lenses.
The work comes in post-processing, as stacking untracked images will produce a result with meteors streaking in many different orientation and locations, ruining the effect of meteors bursting from a single radiant.
To make it easier to stack untracked images, try to include Polaris in the field of the wide-angle lens, perhaps in the upper left corner. The sky rotates around Polaris, so it will form the easy-to-identify point around which you can manually rotate images in editing to bring them back into at least rough alignment.
Covering the steps to composite tracked and untracked meteor shower images is beyond the purview of this blog.
The images shown here were layered, masked and blended with those steps and are used as examples in the book’s tutorials.
A trio of Geminid meteors over the Chiricahua Mountains in southeast Arizona, with Orion and the winter stars setting. I shot this at the end of the night of December 13/14, 2017 with the rising waxing crescent Moon providing some ground illumination. This is a stack of one image for the ground and two fainter meteors, and another image with the bright meteor. The camera was on a Star Adventurer Mini tracker so the stars are not trailed, though the ground will be slightly blurred. All were 30-second exposures at f/2.8 with the 24mm Canon lens and filter-modified Canon 5D MkII at ISO 5000.
Keeping Warm
Keeping yourself warm is important. But your camera is going to get cold. It should work fine but its battery will die sooner than it would on a warm night. Check it every hour, and have spare, warm batteries ready to swap in when needed.
Lenses can frost up. The only way to prevent this is with low-voltage heater coils, such as the DewDestroyer from David Lane. It works very well. Other types are available on Amazon.
A bright comet is a once-a-decade opportunity to capture some unique nightscapes. Here are my suggested tips and FAQs for getting your souvenir shot.
My guide to capturing Comet NEOWISE assumes you’ve done little, if any, nightscape photography up to now. Even for those who have some experience shooting landscape scenes by night, the comet does pose new challenges — for one, it moves from night to night and requires good planning to get it over a scenic landmark.
So here are my tips and techniques, in answers to the most frequently asked questions I get and that I see on social media posts.
Comet NEOWISE (C/2020 F3) over the eroded hoodoo formations at Dinosaur Provincial Park, Alberta, July 14-15, 2020. A faint aurora is at right. The foreground is lit by starlight only; there was no light painting employed here. This is a stack of 12 exposures for the ground to smooth noise, blended with a single untracked exposure of the sky, all at 20 seconds at f/2.8 and ISO 1600, all with the 35mm Canon lens and Canon 6D MkII camera.
How Long Will the Comet be Visible?
The comet is not going to suddenly whoosh away or disappear. It is in our northern hemisphere sky and fairly well placed for shooting and watching all summer.
But … it is now getting fainter each night so the best time to shoot it is now! Or as soon as clouds allow on your next clear night.
As of this writing on July 18 it is still bright enough to be easily visible to the unaided eye from a dark site. How long this will be the case is unknown.
But after July 23 and its closest approach to Earth the comet will be receding from us and that alone will cause it to dim. Later this summer it will require binoculars to see, but might still be a good photogenic target, but smaller and dimmer than it was in mid-July.
This chart shows the position of Comet NEOWISE at nightly intervals through the rest of the summer. However, the rest of July are the prime nights left for catching the comet at its best. Click or tap on the image to download a full-res copy.
When is the Best Time to Shoot?
The comet has moved far enough west that it is now primarily an evening object. So look as soon as it gets dark each night.
Until later in July it is still far enough north to be “circumpolar” for northern latitudes (above 50° N) and so visible all night and into the dawn.
But eventually the comet will be setting into the northwest even as seen from northern latitudes and only visible in the evening sky. Indeed, by the end of July the comet will have moved far enough south that observers in the southern hemisphere anxious to see the comet will get their first looks.
Comet NEOWISE (C/2020 F3) over the Red Deer River from Orkney Viewpoint north of Drumheller, Alberta, on the morning of July 11, 2020. The sky is brightening with dawn twilight and a small display of noctilucent clouds is on the horizon at right. This is a two-segment vertical panorama with the 35mm Canon lens at f/2.8 and Canon 6D MkII at ISO 200 for 13 seconds each. Stitched with Adobe Camera Raw.
Where Do I Look?
In July look northwest below the Big Dipper. By August the comet is low in the west below the bright star Arcturus. By then it will be moving much less from night to night. The chart above shows the comet at nightly intervals; you can see how its nightly motion slows as it recedes from us and from the Sun.
A selfie observing Comet NEOWISE (C/2020 F3) with binoculars on the dark moonless night of July 14/15, 2020 from Dinosaur Provincial Park, Alberta. A faint aurora colours the sky green and magenta. The faint blue ion tail of the comet is visible in addition to its brighter dust tail. The ground is illuminated by starlight and aurora light only. This is a blend of 6 exposures stacked for the ground (except me) to smooth noise, and one exposure for the sky and me, all 13 seconds at f/2.5 with the 35mm lens and Canon 6D MkII at ISO 6400. Topaz DeNoise AI applied.
What Exposures Do I Use?
There is no single best setting. It depends on …
— How bright the sky is from your location (urban vs a rural site).
— Whether the Moon is up — it will be after July 23 or so when the Moon returns to the western sky as a waxing crescent.
— The phase of the Moon — in late July it will be waxing to Full on August 3 when the sky will be very bright and the comet faint enough it might lost in the bright sky.
However, here are guidelines:
— ISO 400 to 1600
— Aperture f/2 to f/4
— Shutter speed of 4 to 30 seconds
Unless you are shooting in a very bright sky, your automatic exposure settings are likely not going to work.
As with almost all nightscape photography you will need to set your camera on Manual (M) and dial in those settings for ISO, Aperture and Shutter Speed manually. Just how is something you need to consult your camera’s instruction manual for, as some point-and-shoot snapshot cameras are simply not designed to be used manually.
A once-in-a-lifetime scene — A panorama of the dawn sky at 4 am on July 14, 2020 from Waterton Lakes National Park, Alberta, Canada with Comet NEOWISE (C/2020 F3) over the iconic Prince of Wales Hotel. Noctilucent clouds glow below the comet in the dawn twilight. Venus is rising right of centre paired with Aldebaran and the Hyades star cluster, while the Pleiades cluster shine above. The waning quarter Moon shines above the Vimy Peak at far right. The Big Dipper is partly visible above the mountain at far left. Capella and the stars of Auriga are at centre. This is an 8-segment panorama with the 35mm Canon lens at f/2.5 for 15 seconds each at ISO 100 with the Canon 6D MkII and stitched with Adobe Camera Raw.
Exposure Considerations
As a rule you want to …
— Keep the ISO as low as possible for the lowest noise. The higher the ISO the worse the noise. But … do raise the ISO high enough to get a well-exposed image. Better to shoot at ISO 3200 and expose well, than at ISO 800 and end up with a dark, underexposed image.
— Shoot at a wide aperture, such as f/2 or f/2.8. The wider the aperture (smaller the f-number) the shorter the exposure can be and/or lower the ISO can be. But … lens aberrations might spoil the sharpness of the image.
— Keep exposures short enough that the stars won’t trail too much during the exposure due to Earth’s rotation. The “500 Rule” of thumb says exposures should be no longer than 500 / Focal length of your lens.
So for a 50mm lens exposures should be no longer than 500/50 = 10s seconds. You’ll still see some trailing but not enough to spoil the image. And going a bit longer in exposure time can make it possible to use a slower and less noisy ISO speed or simply having a better exposed shot.
The histogram as shown in Adobe Camera Raw. Cameras also display the image’s histogram in the Live View preview and in playback of recorded images. Keep the histogram from slamming to the left.
— Avoid underexposing. If you can, call up the “histogram”— the graph of exposure values — on the resulting image in playback on your camera. The histogram should look fairly well distributed from left to right and not all bunched up at the left.
This is Comet NEOWISE (C/2020 F3) over the badlands and formations of Dinosaur Provincial Park, Alberta, on the night of July 14-15, 202. This is a blend of 6 exposures for the ground stacked to smooth noise, with a single exposure for the sky, with the 35mm Canon lens and Canon 6D MkII. The ground exposures are 1- and 2-minutes at ISO 1600 and f/2.8, while the single untracked sky exposure was 20 seconds at ISO 3200 and f/2.5.
When and where you are will also affect your exposure combination.
If you are at a site with lots of lights such as overlooking a city skyline, exposures will need to be shorter than at a dark site.
And nights with a bright Moon will require shorter exposures than moonless nights.
Take test shots and see what looks good! Inspect the histogram. This isn’t like shooting with film when we had no idea if we got the shot until it was too late!
What Lens Do I Use?
With a 35mm lens. Comet NEOWISE (C/2020 F3) over a ripening canola field near home in southern Alberta, on the night of July 15-16, 2020. This is a blend of a stack of six 2-minute exposures at ISO 3200 and f/5.6 to smooth noise, provide depth of field, and bring out the colours of the canola, blended with a single short 15-second exposure of the sky at f/2.8 and ISO 1600, all with the 35mm lens and Canon 6D MkII camera.
With a 50mm lens. Comet NEOWISE (C/2020 F3) over a ripening canola field near home in southern Alberta, on the night of July 15-16, 2020. This is a blend of a stack of three 2-minute exposures at ISO 1600 and f/5 to smooth noise, provide depth of field, and bring out the colours of the canola, blended with a single short 15-second exposure of the sky at f/2.8 and ISO 3200, all with the 50mm Sigma lens and Canon 6D MkII camera.
Any lens can produce a fine shot. Choose the lens to frame the scene well.
Using a longer lens (105mm to 200mm) does make the comet larger, but … might make it more difficult to also frame it above a landscape. A good choice is likely a 24mm to 85mm lens.
A fast lens is best, to keep exposure times below the 500 Rule threshold and ISO speeds lower. Slow f/5.6 kit zooms can be used but do pose challenges for getting well exposed and untrailed shots.
Shooting with shorter focal lengths can help keep the aperture wider and faster. Long focal lengths aren’t needed, especially for images of the comet over a landscape. Avoid the temptation to use that monster 400mm or 600mm telephoto wildlife lens. Unless it is on a tracker (see below) it will produce a trailed mess. It is best to shoot with no more than a 135mm telephoto, the faster the better, IF you want a close-up.
Planetarium programs that I recommend below offer “field of view” indicators so you can preview how much of the horizon and sky your camera and lens combination will show.
StarryNight™ and other programs offer “Field of View” indicator frames that can show how the scene will frame with (in this example) lenses from 24mm to 135mm.
Can I Use My [insert camera here] Camera?
Yes. Whatever you have, try it.
However, the best cameras for any nightscape photography are DSLRs and Mirrorless cameras, either full-frame or cropped frame. They have the lowest noise and are easiest to set manually.
In my experience in teaching workshops I find that the insidious menus of automatic “point-and-shoot” pocket cameras make it very difficult to find the manual settings. And some have such noisy sensors they do not allow longer exposures and/or higher ISO speeds. But try their Night or Fireworks scene modes.
It doesn’t hurt to try, but if you don’t get the shot, don’t fuss. Just enjoy the view with your eyes and binoculars.
But … if you have an iPhone11 or recent Android phone (I have neither!) their “Night scene” modes are superb and use clever in-camera image stacking and processing routines to yield surprisingly good images. Give them a try — keep the camera steady and shoot.
This is Comet NEOWISE (C/2020 F3) over Deadhorse Lake near Hussar in southern Alberta, taken just after midnight on July 10-11, 2020 during its evening appearance. The comet shines just above low noctilucent clouds. This is a blend of nine exposures for the ground stacked to smooth noise and the water, with a single exposure for the sky, all 4 seconds with the 135mm Canon lens at f/2 and Canon 6D MkII at ISO 1600.
What No One Asks: How Do I Focus?
Everyone fusses about “the best” exposure.
What no one thinks of is how they will focus at night. What ruins images is often not bad exposure (a lot of exposure sins can be fixed in processing) but poor focus (which cannot be fixed later).
On bright scenes it is possible your camera’s Autofocus system will “see” enough in the scene to work and focus the lens. Great.
On dark scenes it will not. You must manually focus. Do that using your camera’s “Live View” function (all DSLRs and Mirrorless cameras have it — but check your user manual as on DSLRs it might need to be activated in the menus if you have never used it).
The Live View screen of a Canon DSLR. Look in your manual for tips on how to boost the Live screen image brightness with the Exposure Simulation option.
Magnify the image 5x, 10x or more with the Zoom box centred on a star to focus the star to a pinpoint.
Aim at a bright star or distant light and magnify the image 5x or 10x (with the + button) to inspect the star or light. Put the lens on MF (not AF) and focus the lens manually to make the star as pinpoint as possible. Do not touch the lens afterwards.
Practice on a cloudy night on distant lights.
All shooting must be done with a camera on a good tripod. As such, turn OFF any image stabilization (IS), whether it be on the lens or in the camera. IS can ruin shots taken on a tripod.
What Few Ask: How Do I Plan a Shoot?
Good photos rarely happen by accident. They require planning. That’s part of the challenge and satisfaction of getting the once-in-a-lifetime shot.
To get the shot of the comet over some striking scene below, you have to figure out:
— First, where the comet will be in the sky,
— Then, where you need to be to look toward that location.
— And of course, you need to be where the sky will be clear!
The free web version of Stellarium shows the comet, as do the paid mobile apps.
Planning Where the Comet Will Be
Popular planning software such as PhotoPills and The Photographer’s Ephemeris can help immensely, but won’t have the comet itself included in their displays, just the position of the Sun, Moon and Milky Way.
For previewing the comet’s position in the sky, I use the planetarium programs Starry Night (desktop) or SkySafari (mobile app). Both include comet positions.
The program Stellarium (stellarium.org) is free for desktop while the mobile Stellarium Plus apps (iOS and Android) have a small fee. There is also a free web-based version at https://stellarium-web.orgBe sure to allow it to access your location.
Set the programs to the night in question to see where the comet will be in relation to the stars and patterns such as the Big Dipper. Note the comet’s altitude in degrees and azimuth (how far along the horizon it will be). For example, an azimuth of 320° puts it in the northwest (270° is due west; 0° or 360° is due north, 315° is directly northwest).
Comet NEOWISE (C/2020 F3) with a small display of noctilucent clouds over Emerald Bay and the iconic Prince of Wales Hotel at Waterton Lakes National Park, Alberta, at dawn on July 14, 2020. This is a blend of a stack of four exposures for the ground and water to smooth noise, blended with a single short exposure for the sky, all 20 seconds at f/2.5 and ISO 400. All with the 35mm Canon lens and Canon 6D MkII camera.
With either you can dial in the time and date and see lines pointing toward where the Sun would be, but below the horizon. Scrub through time to move that line to the same azimuth angle as where the comet will be and then see if the comet is sitting in the right direction.
The screen from The Photographer’s Ephemeris app showing the planning map for the image above, with the faint yellow line indicating the line toward the comet’s azimuth.
Move your location to place the line toward the comet over what you want to include in the scene.
The simulation of the real scene above, of the comet over the Prince of Wales Hotel, using TPE 3D app. The simulation matches the real scene very well!
I like The Photographer’s Ephemeris as it links to the companion app TPE3D that can show the stars over the actual topographic landscape. It won’t show the comet, but if you know where it is in the sky you can see if if will clear mountains, for example.
The Astrospheric app prediction of skies for me for the night I prepared this blog. Not great! But clear skies could be found to to east with a fresh hours drive.
Planning for the Weather
All is for nought if the sky is cloudy.
For planning astro shoots I like the app Astrospheric (https://www.astrospheric.com). It is free for mobile and there is a web-based version. It uses Environment Canada predictions of cloud cover for North America. Use it to plan where to be for clear skies first, then figure out the best scenic site that will be under those clear skies.
Be happy to get a well-composed and exposed single shot.
But … if you wish to try some more advanced techniques for later processing, here are suggestions.
A panorama of the sky just before midnight on July 13, 2020 from Waterton Lakes National Park, Alberta, Canada with Comet NEOWISE (C/2020 F3) over the front range of the Rocky Mountains and an arc of aurora across the north. This is a 6-segment panorama with the 35mm Canon lens at f/2.2 for 25 seconds each at ISO 800 with the Canon 6D MkII and stitched with Adobe Camera Raw.
1. Panoramas
On several nights I’ve found a panorama captures the scene better, including the comet in context with the wide horizon, sweep of the twilight arch or, as we’ve had in western Canada, some Northern Lights.
Take several identical exposures, moving the camera 10 to 15 degrees between images. Editing programs such as Lightroom, Adobe Camera Raw, ON1 Photo RAW and Affinity Photo have panorama stitching routines built in.
My Nightscapes and Time-Lapses ebook shown above provides tutorials for shooting and processing nightscape panoramas.
What a magical scene this was! This is Comet NEOWISE (C/2020 F3) over the sweep of the Red Deer River and Badlands from Orkney Viewpoint north of Drumheller, Alberta, on the morning of July 11, 2020. Light from the waning gibbous Moon provides the illumination, plus twilight. This nicely shows the arch of the twilight colours. This is a 6-segment panorama with the 50mm Sigma lens at f/2.8 and Canon 6D MkII at ISO 400 for 13 seconds each. Stitched with Adobe Camera Raw. Topaz DeNoise AI and Sharpen AI applied.
2. Exposure Blending
If you have a situation where the sky is bright but the ground is dark, or vice versa, and one exposure cannot record both well, then shoot two exposures, each best suited to recording the sky and ground individually.
For example, on moonless nights I’ve been shooting 2- to 5-minute long exposures for the ground and with the lens stopped down to f/5.6 or f/8 for better depth of field to be sure the foreground was in focus.
This is Comet NEOWISE (C/2020 F3) over the Horseshoe Canyon formation near Drumheller, Alberta on the night of July 10-11, 2020, taken about 2 a.m. MDT with the comet just past lower culmination with it circumpolar at this time. Warm light from the rising waning gibbous Moon provides the illumination. This is a blend of six 1- and 2-minute exposures for the ground at ISO 800 and 400 stacked to smooth noise, with a single 30-second exposure at ISO 1600 for the sky, all with the 35mm Canon lens at f/2.8 and Canon 6D MkII.
3. Exposure Stacking
To reduce noise, it is also possible to shoot multiple exposures to stack later in processing to smooth noise. This is most useful in scenes with dark foregrounds where noise is most obvious, and where I will stack 4 to 8 images.
Just how to do this is beyond the scope of this blog. I also give step-by-step tutorials for the process in my Nightscapes and Time-Lapses ebook shown above. It be done in Photoshop, or in specialized programs such as StarryLandscapeStacker (for MacOS) or Sequator (Windows).
But shoot the images now, and learn later how to use them.
A close-up of Comet NEOWISE (C/2020 F3) on the night of July 14/15, 2020 with a 135mm telephoto lens. This is a stack of nine 1-minute exposures with the 135mm Canon lens wide-open at f/2 and Canon EOS Ra camera at ISO 800. The camera was on the iOptron SkyGuider Pro tracker tracking the stars not the comet. Stacked and aligned in Photoshop.
4. Tracking the Sky
If it is close-ups of the comet you want, then you will need to use a 135mm to 300mm telephoto lens (especially later in the summer when the comet is farther away and smaller).
But with such lenses any exposure over a few seconds will result in lots of trailing.
The iOptron SkyGuider Pro and 135mm lens used to take the close-up shot of the comet above.
The solution is a tracking device such as the Sky-Watcher Star Adventurer or iOptron SkyGuider. These need to be set up so their rotation axis aims at the North Celestial Pole near Polaris. The camera can then follow the stars for the required exposures of up to a minute or more needed to record the comet and its tails well.
This is the Sky-Watcher Star Adventurer. All trackers have a polar axis that needs to be aligned to the Celestial Pole, near Polaris.
Just how to use a tracker is again beyond the scope of this blog. But if you have one, it will work very well for comet shots with telephoto lenses. However, trackers are not essential for wide-angle shots, especially once the Moon begins to light the sky.
But later in the summer when the comet is fainter and smaller, a tracked and stacked set of telephoto lens images will likely be the best way to capture the comet.
A bright comet is a once-a-decade opportunity to capture some unique nightscapes. Here are my suggested tips and FAQs for getting your souvenir shot.
The Amazing Sky 