Cassiopeia is a prominent northern constellation named after the vain queen of Greek mythology. Notable for its distinctive “W” asterism formed by five bright stars, it lies along the plane of the Milky Way and contains many deep-sky objects, including the supernova remnant Cassiopeia A and star‑forming regions such as IC 63.
Source: nasa.gov
17/06/2003

It's the bubble versus the cloud. NGC 7635, the Bubble Nebula, is being pushed out by the stellar wind of massive central star BD+602522. Next door, though, lives a giant molecular cloud, visible above to the lower right. At this place in space, an irresistible force meets an immovable object in an interesting way. The cloud is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the bubble's central star. The radiation heats up dense regions of the molecular cloud causing it to glow. The Bubble Nebula, pictured above as a color negative to help bring up contrast, is about 10 light-years across and part of a much larger complex of stars and shells. The Bubble Nebula can be seen with a small telescope towards the constellation of Cassiopeia.