Another interesting object is NGC7635 also known as the Bubble Nebula in the constellation of Cassiopeia.
It’s the result of massive stars in the region that create fast-moving gas which spreads out from the star BD +60° 2522. Pushing surrounding sparse gas into a shell. The energetic starlight then ionizes the shell, causing it to glow.
The image data for this was obtained over 2 different clear nights and from 2 different locations, our family cottage on the shore of Lake Huron and the dark site between Conestoga Lake and Listowel, Ontario.
It’s a total of 4 hours obtained with a Canon 350xt DSLR and an Equinox 80mm ED APO refractor with a 0.8x reducer/field flattener.
Equipment: Skywatch Equinox 80mm ED APO refractor, William-Optics 0.8x FF/RR, Canon (modified) 350XT DSLR. 400mm FL
Software: Nebulosity 3 for acquisition, calibration and alignment. PHD for auto guiding.
Exposure: Total of 4 hours / 5min subs.
Processed in Photoshop.