Andromeda Galaxy (M31) 9-28-25

The Andromeda Galaxy (M31) is one of the most prominent deep space objects in the northern sky and among the easiest to visually observe, along with the Orion Nebula and the Pleiades. Andromeda is about 2.5 million lightyears away, making it one of our closest galactic neighbors. Visible on the near side of Andromeda is satellite galaxy M32 (right of center), and on the far side is satellite galaxy M110 (top left).

I had some trouble with my tracking mount during this imaging session, which upon reflection may have been due to poor counterweight placement. As a result, my exposures were only 15 seconds each. That said, I have improved my post-processing workflow a lot after creating my image of the Pinwheel Galaxy. Before this project, my understanding of the theory behind histogram stretching was limited, and I was just beginning to learn how to use Siril. I spent some time researching both (thank you to Cosmic Curiosity on YouTube!) and managed to correct some earlier flaws in my process. This was my first time successfully editing an image using Starnet++ star removal and recombination. While I did experiment with fixing asymmetrical stars using full resynthesis, I decided the result looked artificially perfect in a way that felt forced.

Technical details:

• Lens: Sky-Watcher StarTravel 120
• Camera: Nikon D3200
• Mount: Sky-Watcher Star Adventurer 2i
• Optics: Explore Scientific Field Flattener
• Filters: SVBONY UHC
• Exposure: 504x15s at ISO1600
• Corrections: 50 darks, 50 flats, 50 dark flats
• Stacking: Siril
• Post-processing: Siril, GIMP
• Bortle: 4

Notes for improvement:

• Double-check counterweight balance after moving the scope to the approximate RA and dec position of the target. I probably set my counterweights with the scope at a declination that was not representative of my actual imaging orientation, which could have caused my tracking issues.
• As always, more data!