Bubble Nebula. Open star cluster Messier 52 in Cassiopeia.

The Bubble Nebula. Open star cluster Messier 52 in Cassiopeia Mount: MT-90 Optics: Celestron C8N 200mm f/5, TS-Optics MONORAIL 2" Dual Speed Focuser Camera: ZWO ASI 533C Pro Filter: Optolong L-eXtreme Guide Scope: Svbony 60/240 Guide Camera: T7 Astro Total Integration: 1.92 hours Single Frame Exposure: 300 seconds Bin: 1x1, Sensor Temperature: 0°C ISO/Gain: 100 Full calibration with 20 frames each (darks, biases, flats) Processing: DSS, FITStacker, Ps. Sky Brightness: Bortle Orange Zone. Date: September 10, 2021