Photographing Comets From Your Backyard

23,070

138

21

Introduction: Photographing Comets From Your Backyard

About: I'm a professor of physics and astronomy at Northwestern University. I do a lot of hobbies, including amateur astronomy, woodworking, and Lego modeling among many others.

Comets are rare and beautiful phenomena. It is not often that they pass by the Earth and are visible enough to be seen by virtually everyone.

The appearance of Comet NEOWISE (the astronomer catalog number is C/2020 F3) has sent droves of us into our backyards in the early evening hours to see the spectacle. If your skies are dark enough, it is visible to the naked eye, and even if you live under city lights it can usually be found with a pair of binoculars.

The sight of such cosmic wonders often inspires a deep desire to capture the view as a picture, for later contemplation. If you have a modern DSLR (digital SLR), this Instructable will show you how I capture pictures of the comet. I took the picture above from my backyard in suburban Chicago. You can do it too!

NEOWISE will certainly not be the last comet to grace our skies, so file these instructions away, and keep them handy when the next one swings by.

Step 1: But I Don't Have a DSLR!

Even if you don't have a DSLR, you can still try and capture the comet in an image. All you really need is the ability to make sensitive pictures in near darkness ("night mode"), or exposures between 1 and 5 seconds long.

The image above was captured by my daughter using an iPhone 11! The image is grainy, but the comet is definitely there! If you browse the web, you'll find many examples of phone pictures taken of the comet, and can get some inspiration.

Step 2: Basic Equipment

To follow these isntructions, you need:

  • Digital SLR (I have a Canon T3i)
  • Any lens (I've shot the camera with both of my lenses!)
  • Binoculars (to enjoy looking at the comet with your eyeballs)
  • Tripod

If you've never futzed around with your DSLR before, it is best to try it indoors before you go out, just to know where all the buttons are. There aren't many you need to know to follow this Instructable, but it will be easier in your dining room, rather than in the dark in your backyard!

The tripod is simply to hold the camera still during the multi-second exposure; the camera does not need to track the comet to get a good picture of it! If you have a shutter release cable, you can use it to remotely trigger the shutter, but I haven't had any problems just pushing the shutter button if the camera is mounted on my tripod.

Step 3: Finding NEOWISE

At the moment, Comet NEOWISE is visible to people in the northern hemisphere, about an hour after sunset, in the northwest skies. It should be visible for at least the next 7 to 10 days (until early August 2020).

The chart above shows the location of NEOWISE for the next couple of weeks as it moves slowly across the sky. The Big Dipper is the most prominent group of stars near the comet, and it has been marked here in orange. It is usually visible, even if you live in a fairly bright city.

When you first go out, face to the Northwest, and see if you can identify the Big Dipper. Sweep your eyes back and forth in the area below the Big Dipper -- more than likely your eye will be able to see the comet, though you may only be able to see the bright head of the comet (called the "coma") and you'll think it is a star.

This is where you binoculars come in. My binoculars are shown above -- they're the ones I keep on my coffee table and use to watch squirrels and birds. Using your binoculars, look for a bright star (any bright star) and make sure the star looks focused.

Now sweep the binoculars back and forth under the Big Dipper slowly, and you should be able to find the comet after a few passes. If you can't find it, wait maybe 10 or 15 minutes, until it gets a bit darker then try again.

Once you find it in binoculars, you may know enough what you are seeing to spot it with your unaided eye.

Step 4: Camera Settings

There are no perfect settings to get the perfect comet picture.

ISO SETTINGS. I typically shoot at ISO 800, or ISO 1600. ISO 800 pictures are darker, but ISO 1600 pictures are a little bit grainier.

EXPOSURE. I use the "Manual" (M) mode, so I can control all the settings, including the shutter speed. I have experimented with exposures between 1 second and 6 seconds. There is enough light pollution around me that 6 second exposures are pretty washed out, so I usually settle in around 4 second exposures.

These settings will get you started, and you can look at each picture you take on your viewscreen and see if you can see the comet. If not, increase your exposure or increase your ISO.

Don't feel rushed -- each night, the comet will be visible for an hour or more, so take some time to experiment with the settings to see what gives you a good image. We'll talk a bit about post processing in Step 8.

Step 5: Focusing Your Camera: Live View Mode

Focusing your camera for sky pictures is the most involved part of this exercise. Almost nothing you can photograph in the sky is bright enough for the auto-focus to work on (the notable exception is the Moon), so turn the autofocus off.

The magical trick to focusing for night sky pictures is to use "Live View."

On most DSLRs you can look through the viewfinder, holding the camera up to your eye like a traditional photographer would. Live View blocks the viewfinder and instead sends the image to the viewscreen on your camera.

There should be a button to switch between the ViewFinder and the LiveView -- on my camera, it is right next to the view finder, as shown in the 1st picture above. When you switch to LiveView, the screen displays what the camera is seeing, as shown in the 2nd picture above.

The last thing you need to know about LiveView is how to magnify. On my camera, the selection button on the back of the camera body, just below the shutter button. It switches LiveView between 1x, 4x, and 10x magnification. We are going to use the 10x mode for focusing.

Step 6: LiveView Focusing in the Dark

To get focused using Live View, look for a bright star, the brightest one you can see. Right now there is one high in the sky called Vega, slightly to the east of overhead.

Start with your focus turned all the way to infinity -- it won't be perfect for astro pictures, but it will be close enough to get us ready to focus.

  • Switch your camera to LiveView
  • Point your camera at this bright star, and get it in the center box on your screen (1st image)
  • Magnify the LiveView to 10x (2nd image); the star will be unfocused
  • Watching the LiveView, make small manual adjustments to the focus until the star is as much like a point as you can get it (3rd image)

At this point you are focused. Do not change the focus!

Tip your camera down, and turn it toward the region of the sky where the comet is. You're ready to go!

(Author's Note: the hardest thing about making this Instructable was photographing the LiveView screen in the dark!)

Step 7: Take a Picture of the Comet!

Here are two pictures directly off the camera, without any processing.

1st Image: ISO 800, 3 second exposure

2nd Image: ISO 1600, 5 second exposure

These pictures were taken on two different nights, from slightly different locations in my backyard. I like the trees in the foreground, since they provide a little bit of composition, and help give the image a sense of scale.

These images certainly show the comet, but a little post processing in a photo-editing program can improve the visibility.

Step 8: Adjusting Image Brightness

Programs like Photoshop can give you very precise and varied control over virtually every aspect of a digital image, but knowing what to do is mind-boggling if you are a beginner.

Fortunately, most comet images directly off your camera can benefit from simple adjustments of the levels. The images above are the same two images from the last step, but have been adjusted using the simple "Adjust Level" features in the Macintosh "Preview" Application. "Paint" or Image Viewing applications on Windows should have similar functionality (any Windows users reading this, let me know in the comments what to tell people!).

Under the Tools Menu, select "Adjust Color..." and the control window will pop up.

1st Image: In this image, I simply tapped "Auto Levels" and you can see the software blows the image out; I think it is trying to make the trees look good.

2nd Image: After tapping "Auto Levels", grab the three sliders over the "Auto Levels" button, and slide them back and forth. Generally I adjust the two on the right, and produce a good looking comet image!

3rd Image: Tapping the "Auto Levels" blows out the image

4th Image: Moving the sliders rebalances the image into a nice comet picture.

Step 9: Post Your Pictures!

That is everything I know about taking comet pictures! Try and take a few of your own, and send them to your family and post them to social media!

If you found this Instructable helpful, post your comet pictures in the comments!

I leave you with a few of my best Comet NEOWISE pictures -- check out the fireflies!

Happy Comet Hunting!

Backyard Contest

Runner Up in the
Backyard Contest

8 People Made This Project!

Recommendations

  • Lighting Challenge

    Lighting Challenge
  • Make It Fly Speed Challenge

    Make It Fly Speed Challenge
  • Colors of the Rainbow Contest

    Colors of the Rainbow Contest

21 Discussions

1
plasticdinko
plasticdinko

8 days ago

Hey, I really appreciate the work that you have done to publish this wonderful guide.
I cannot wait to try it all out. Thanks! 😃

0
gravitino
gravitino

Reply 5 days ago

Thanks! I'm glad you found it useful!

2
Mamvcivm
Mamvcivm

8 days ago

These three photos (taken at 200mm with a Canon 60D) show the difference with shutter speed & ISO - the first one was 2.5sec ISO1000, the second was 10sec at ISO200, both f/3.2, they were taken just after midnight on the 12th July. The comet was easily visible through naked eye, even over murky Manchester skies. The third photo was taken a week later just before midnight on the 19th. It too was 2.5sec at ISO1000 albeit at f/2.8. By that date, the comet was just visible by naked eye and the tail seemed much shorter.

_MG_2258.jpg_MG_2259.jpg_MG_2287.jpg
1
gravitino
gravitino

Reply 5 days ago

Those are really great shots!

1
shalnachywyt
shalnachywyt

8 days ago on Step 2

I've been having trouble just finding the comet, but your illustrations have helped me, so I'm going to see if I can do this with my crappy 3" telescope that someone threw out in the trash and that I rescued. I've been able to take pics of the moon using my 7mpix Casio point-and-shoot, so this will be an interesting experiment.
Thanks for the instructable and the inspiration.

0
gravitino
gravitino

Reply 5 days ago

I hope you found the comet! Glad you found the instructable useful!

0
cromorepetido
cromorepetido

8 days ago on Step 7

Great. A very good "exposure". I took a photo of the comet on the 16th. I will optimize the exposure with the base of its explanations and I will make another photo that will be better. Thanks a lot for sharing your experience.
1
ralph.peteranderl
ralph.peteranderl

Tip 9 days ago on Step 9

Manual focus is really important. At first I used AF with manual over-ride, Looks good when you check out the image at the start of the exposure. But then my camera will try to re-focus and it all turns to blur

0
gravitino
gravitino

Reply 8 days ago

I remember once when I was just starting to tinker with astrophotography I had left auto-focus on and it tried to focus EVERY TIME the intervalometer tried to trigger the shutter. It was (in my memory) rather comical. :-)

0
Valvelifter
Valvelifter

9 days ago on Step 7

I have used several image processing programs and am now using Darktable (open source i.e.free) IMO the most outstanding, powerful image processor and ideal for getting the best out of astrophotography.

Comet2.jpg
0
gravitino
gravitino

Reply 8 days ago

Thanks! I see it has wide OS support which is always an issue for me (I'm a Mac user) so knowing about useful processing software is useful!

1
rnshagam
rnshagam

8 days ago

I used a planetarium program--Carte du Ciel--and Google Maps and GIMP (all freeware) to plan and process this shot :

C-2020-f3-NEOWISE-7-12a.jpg
0
gravitino
gravitino

Reply 8 days ago

Nice! Didn't know about this software -- I'll check it out!

I made the chart in Step 3 with STARRY NIGHT; people may also find STELLARIUM (open source planetarium software) useful for this kind of planning. http://stellarium.org

1
metalfury
metalfury

Tip 8 days ago

Did this last night, great instructable thanks for sharing.

Couple of extra tips, mainly for DSLR users:

• Wack the ISO up to max and quicken the shutterspeed when composing your shots. Allows you to quickly take and adjust composition before returning to your longer shutterspeed. For my location I couldn't see anything on the viewfinder, so had to play by ear!

• Turn off image stabilisation on the lens if you have it.

• Check out up the 500 rule for shutterspeeds to avoid star trails. (essentially for my camera the number of seconds shutter speed = 500 / (Focal length from lens x 1.6) )

• I had a little red torch to keep my 'night vision', but the most helpful thing was knowing how to adjust the shutterspeed/iso without being able to see.

• Make the aperture as low as the lens will go

• Reduce the brightness on the LCD panel

• Shoot in Raw

• Use a 2 second delay on the drive if you have it to avoid camera shake on button pressing.

• Have fun!

0
gravitino
gravitino

Reply 8 days ago

Thanks! these are great tips too. I'm simultaneously learning to shoot at night but also all the DSLR things/photography things I should know. Tips from everyone like these are a great help!

1
WoodyH1
WoodyH1

8 days ago

I noticed you were using an f5. 6. Try opening the lens aperture to a lower f-stop. Perhaps F 1.4 or a f 2.0or a f 2.8.
This opens the lens up considerably and is dependent on the capability of your Linens. As with any telemetric experience when you're dealing with such little light you want to be able to gather as much light as possible for the best quality image. This will affect your depth of field but then we are talkin about photographing something that's suspended in space so it's a black depth of field and generally doesn't really matter.

0
gravitino
gravitino

Reply 8 days ago

Hi Woody! Yes, but that is the only lens I have and the fastest f-stop I have. But those are all great points -- learning photography by osmosis, especially at night, is hard. Tips from all of you are a great help!

0
WoodyH1
WoodyH1

Reply 8 days ago

Just a side note. I remember that you said you live in are somewhat urban area. The lower f-stop may be an issue if you live in a urban or Suburban location due to the light pollution. It really depends on your particular situation and weather the light pollution is behind you or in front of you. However if you live out in the country like I do, I live in North Central Nevada in a small town of 4,000 people where the nearest light pollution is quite literally 200 miles away, you can go down to the lowest f-stop and get some incredible pictures.

0
WoodyH1
WoodyH1

Reply 8 days ago

Another side note. I just re-read my first side note. You got to love spell correct when you're using voice to text on a cell phone 😂