Messier 81 & Messier 82 (RGB)

Near the start of my astrophotography journey I did an image of M81 & M82 using a DSLR and a 200mm lens. It wasn’t very good though I was quite excited about it at the time. Now, I have a refractor though the focal length is still fairly short at 480mm but I also have a mono camera and red, green and blue filters along with a hydrogen alpha filter and I wanted to see what I could do with drizzle integration to maximize detail.

I acquired the data between January and March 2020. It turns out I had a problem with my red, green and blue flat frames and I thought I was going to have to throw away the data and start over but retaking the flats worked well enough though not perfectly.

My first attempt to process the image failed miserably and I ended up sitting on the data for a month figuring I’d get more data and see how that helped. As it turned out, the last month has been cloudy, rainy or (on the one clear night) windy. A member of the local imaging group posted a hydrogen alpha mono image of M82 (the galaxy on the right) and it inspired me to try again.

It took a couple of tries but I finally came up with this version which has the pretty good detail and the galaxy blends fairly naturally into the background. If you want to see a full resolution version or the technical details, check out the image on astrobin.

As to the galaxies…they are about 11.7 light years away. M81 is a conventional spiral galaxy, similar to but smaller than our own. M82 is a “starburst galaxy”. It is creating stars at a rate about 10 times that of the Milky Way and though smaller than the Milky Way it outputs about five times as much light.

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