This stunning image features a deep field view of the Cassiopeia constellation where the two small planetary nebulas can be ...

Abell 7, a very faint planetary nebula, is located about 1,800 light-years from Earth (1 light-year is the distance light travels in a year, approximately 9.46 trillion kilometers). From Earth ...

The other small bright bluish ball visible to the left of center in the image is known as Abell 6. This small planetary nebula, like others like it, was formed by gases in the outer layers of a ...