The Bubble Nebula (NGC 7635, Sharpless 162, or Caldwell 11), is a hydrogen line emission nebula in the constellation Cassiopeia. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575 pushing the gas away in an expanding wavefront. The nebula is near a giant molecular cloud that is also being excited by the hot central star providing the glowing background nebulosity. The Bubble Nebula was discovered in 1787 by William Herschel, but is difficult to detect visually with anything but the larger amateur telescopes in extremely dark skies.

This image is a stack of fifty ten-minute exposures (8.3 hours of integration time) taken using my QHY247C with my 11" Edge HD mounted on my CGE Pro. The images were stacked in DSS and processed in PixInsight (my first end-to-end attempt with this tool) and final touches in Photoshop. For an interesting comparison, check out this attempt from 2010, showing the great improvement in my imaging chain and processing.

Image Center:	View full size annotated image.
Right Ascension:	23h 20m 43.422s (350° 10m 51.331s)
Declination:	+61° 10m 41.604s
Orientation:	Up is 358.6 degrees East of North.
Image Size:	28.827' x 19.216'	Pixel Scale:	0.288"

Principal objects in field: Bubble nebula, NGC 7635

All identified catalog objects: HD 220057, NGC 7635