The Cave Nebula, (Caldwell 9, Sh2-155) Is a challenging target under Bortle 7 skies in Austin with a bright gibbous moon in the sky. This image has almost 12 hours of total exposure at -5C with the RedCat 250/51mm, Optolong L-Ultimate, and ASI533 MC.

Processed in PixInsight, 141 5' exposures w darks, drizzle stacked, Auto DBE, then SPCC, RC-Astro Noise/Blur/StarXTerminator plugins, Star Stretch, and Affinity Photo final exp and crop.

One of my best light frames, a single 5' exposure with the moon down. Auto stretched, dark point increased and cropped for comparison to the final image:

With 3nm dual narrow band filters, I can usually see my target clearly in a 1 minute test shot. With the Cave Nebula, I could barely make it out in the 5’ shots. Amazes me with 2-3 times the data, to find a pony emerge from the shit.