First Galaxy, M101

After spending a few weeks working on an equatorial platform for my telescope, I finally got all the kinks worked out on it and had a nice, clear night to test it. The platform worked exceptionally! I spent about 15 minutes setting it up, fiddling with the motor speed, and aligning it a bit. At the end of the night, I realized that it wasn’t even pointing close to Polaris, but I was still able to start out with six second exposures!

I was unable to see anything in the live view on my laptop with the camera, so I had to just guess and check the sky to finally find the Pinwheel galaxy. This was pretty difficult to do, but I finally found my target. Luckily, I was able to focus on a bright star first before looking around. I say, “pssh!” to those Go-To systems. That takes the fun out of it! But, the excitement and joy I got when one of those six second frames finally loaded on the laptop, and I could see the swirling arms on that galaxy, was unbeatable!

I took almost 300 images of the galaxy, but many of them were bad, off center, or had a bit of trailing in them. I was able to whittle it down to about 130 images where the galaxy was mostly centered in the frame. The “light” frames were preprocessed with many flats, darks, and biases that were taken at the end of the session. This helps to remove a bit of static internal camera noise from the pictures, as well as some mechanical flaws within the telescope. Then, the frames were stacked using average stacking with rejection, but I tried a different rejection scheme this time, choosing “linear fit clipping” as advised by an online tutorial. I think it helped with noise a bit better than the “Windsorized” rejection I had tried in the past. I also had the stacking algorithm only stack the best frames based on star roundness, so bad images featuring major trailing were left out.

Siril has many great image processing tools, such as green noise removal, background removal, background color neutralization, and saturation improvements. Below is my final image, after playing around a few times and noticing that some of my flats were pretty bad. I tried to leave the saturation mostly intact to give a bit more realistic view of the galaxy.

As you can see, plenty of noise is still present in the images. The dimness of these objects is much more than I anticipated when I first got the idea to start photographing the sky. The six second exposures, while impressive for my first test of the equatorial platform, are still not quite enough to get that signal to be significantly above the “shot noise” of the horrid Akron skies. I’ve got an idea for a contraption I can make and use to try to polar align the platform better, and if it works, I am hoping to get ten to fifteen second exposures in my next trial. I also recently received a focal reducer that I would like to try, as that may substantially improve the signal-to-noise ratio of my images. With 6000×4000 pixel images, I always greatly scale down the final images, anyways, so I think the focal reducer might get me just what I am looking for. That is, if I can get a twelve inch f/2.5 scope to agree with me!

As a bonus, in a couple of images, I also got a satellite trailing through the frame! I combined the two frames it was in below.