M31 Andromeda Galaxy 12/9/2021Los Angeles, CA (Bortle Class 9)Nikon Z6William Optics GT71 71mm f/5.9 Triplet RefractorOptolong L-Pro 2″ Deep Sky FilterSky-Watcher Sky Adventurer Mount100 lights; ISO 16,000; 10-second exposures, stackedno flats, darks or biases