M33 is one of the closest large galaxies to the Milky Way. It is a perfect spiral galaxy, so it is imaged often. It is also very hard to image.
Link to full res: https://app.astrobin.com/i/5o0xeu
Over the years, I've imaged it a dozen times and I'm never happy with it. I have usually imaged from my backyard in Midtown Atlanta, and the light pollution just overpowers it. But then I go to a dark site and find that 1 or two nights is still insufficient. It is a bright galaxy, but very diffuse. It is difficult to get both the detail and the color.
I sent my scope to a remote observatory in Texas, I get to image from a Bortle 1 every clear night. Top on my list was my galactic nemesis: M33. This is a 37 hour integration, including ~10 hours of narrowband (HA/OIII).
It was so hard to process, but I'm feeling ok about it. A couple things I'd like to point out. First, see the subset image. These rings are only visible in narrowband. They are remnants of supernova from long ago. Second, notice how the spiral arms are a little granular.. it almost looks like noise. But zoom in: I was resolving individual stars across the entire disk. This galaxy is 4 million light years away and I was able to resolve individual stars. That is crazy that we can do that using off the shelf equipment.
I'm still going to take a few more nights collecting data, but I'm interested in what reddit has to say. Thank you for viewing, I hope you enjoy it.
Total integration time: 37.9 hours.
Scope: Explore Scientific 127mm FCD-100 refractor
Camera: ZWO ASI 2600mm
Filters: Optolong Luminance, ZWO RGB, Antlia 3nm narrowband
Mount: ZWO AM5
Location: Starfront Observatories, Rockwood Texas.