Object: NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an 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. 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.
Taken: August 1, 2019
Telescope: Astro-Tech 14” RC with 0.65x focal reducer
Mount: Paramount ME II unguided
Camera: ZWO ASI1600MM-Pro (cooled to -15C; unity gain) Bin 2×2.
Focuser: Moonlite Nitecrawler
Filters used: H-a, O-III and S-II on a ZWO 8 position filter wheel
Exposures: 25×100 sec each filters, for a total exposure time of 2.08 hours; calibrated with 100 bias frames, 25 dark frames, 32 flat frames with 32 dark-flats. Image was processed in the Hubble (SHO) palette.
Seeing Conditions:
Processed with PixInsight and Photoshop CC 2019