Bubble Nebula (NGC 7635) — Narrowband SHO

The Bubble Nebula (NGC 7635) in Cassiopeia — a seven-light-year shell blown by one hot, massive star, about eleven thousand light-years away. Shot in narrowband S H O (H-alpha, O-I-I-I, S-I-I): 68 frames of 300 s, ~5 h 40 m over three nights, with an 8-inch Skywatcher 200/1000 PDS and a Touptek ATR533M mono camera. Captured in N.I.N.A. with PHD2 guiding, processed in Siril.

Full image and acquisition details in the Bubble Nebula album.