Tag Archives: comet

Comet Stacking

I’ve seen some awesome images of Comet Neowise C/2020 F3. I’m sure you have too. Did you make any photos of it? Then you might have a better image than you think, just waiting to be processed. Let me explain.

Neowise.Central Winds Park. 7/16/20. Single exposure at 85mm, f/2.8, 8s, ISO 400

Lynn and I went up to Central Winds Park in Winter Springs to see if we could spot Neowise. This park is on the south shore of Lake Jesup and has less light pollution to the north than we do in our neighborhood. Once it was dark enough, we could easily find it in binoculars, but it was very hard to pick up with just our eyes.

I went back a few days later with my long lens to try for a close up.

Comet Neowise C/2020 F3

Neowise. Central Winds Park. 7/19/20. 3 exposure stack, 600mm, f/6.3, 2s, ISO 3200 – 6400

I made a lot of frames of the comet on that trip, trying to find optimal settings for a single exposure. Almost all of the really spectacular images that you’ve seen are probably from a tracking mount, with multiple frames that are aligned, stacked, and processed together to reduce noise and bring out faint detail. I wasn’t trying to do any of that.

But after several attempts to get the best image I could out of what I’d captured, I realized I might have multiple frames I could stack too. So going back through my RAW captures I found three photos to try. They weren’t ideal since they were at different ISOs but I thought it was worth a shot. Here’s a before / after of a single RAW image compared to a stacked composite from three frames.

Comparison of a single RAW frame to the stacked, 3 frame final image

If you’re an astrophotographer, you already know all this. And you probably have some task specific software to align / stack / process images. If you’re not an astronomy buff, then do a web search for “photoshop manual align astro layers” and you’ll find a lot of info on how to do this without any extra programs – which is how I processed mine.

This is only the 3rd or 4th comet I’ve seen and the very first that I’ve tried to photograph. The first one I saw was Halley’s Comet back in 1986. I remember how exciting it was to show it to Lynn and Mike. I had a camera (and a telescope) then, but photos like these with that equipment would have been next to impossible. Photography has come such a long way!

So, if you made any Neowise photos, sort through them for frames you can try to stack. You may be surprised at the improvement you can get.

Thanks for stopping by and reading my blog. Hang in there and take care of each other. And if you can – stack some photos!

©2020, Ed Rosack. All rights reserved