Part of a rich field of nebulae and clusters in the northern constellation Cassiopeia, Sharpless 2–157 (below) is sometimes called lobster nebula. The best known bubble nebula is located above the center in this image. Credit: Trevor Jones
As we saw in recent posts, the northern Cassiopeia constellation is full of intriguing nebulae and bright stars clusters. A large and relatively bright emission nebula between this group, Sharpless 2–157, is rarely observed by amateur astronomers. Sometimes it is called lobster claw nebula due to its distinctive form.
This large nebula is located in the vicinity relatively close to the well -known bubble well known and frequently observed (NGC 7635).
Two open clusters are located inside or close to Sharpless 2–157. They are Markarian 50, which are 11,000 light years away and are 7.5 million years and, near the northern edge of the nebula, the bright cluster NGC 7510. The latter lights up at the eighth magnitude, extends 7 ‘, is located 11,000 light years away and is about 10 million years.
The northern part of Sharpless 2–157, sometimes identified as Sharpless 2–157a, contains a circular nebula that surrounds a star -ray star, WR 157, which is ionizing the surrounding gas.
