NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575 (BD+60°2522). The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel. The star BD+60°2522 is thought to have a mass of about 44 M☉.

ES CF102 Triplet
AVX Mount
Stellarvue 0.8x flattener/reducer
Canon D40 (Astro modification)
Filters:
Astronomik Clip on Ha 6nm.
Astronomik Clip on OIII 6nm.
Astronomik Clip on CLS / Nebula filter

12.7 hours of integration time
60 x 280" Ha
60 x 280" OIII
42 x 300" Lum
Plus numerous Dark, Flat & Bias frames.
Stacked in DSS / Post-processing & dynamic cropping in PixInsight
Final tone touches in GIMP2 and Raw Therapee