NGC 7635, taken on September 4th, 2017 is also called the Bubble Nebula, Sharpless 162, or Caldwell 11, is a H II region[2] emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. Seen to the left side of the picture. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, the 15 ± 5 M☉[4] 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 Friedrich Wilhelm Herschel.