Object CRL 2688, the Egg Nebula, is a proto-planetary nebula located in the constellation Cygnus, at a distance of about 3,000 light years from Earth. Based on its angular size of about 25 arc seconds, scientists estimate it is about 0.4 light years across. It represents a transitional stage between the final death stages of a star similar to our sun, and the formation of a planetary nebula. The central star of the nebula, which is hidden from us by dust, is thought to have been a red giant only several hundred years ago. The Egg Nebula is a reflection nebula, illuminated by the star from which it is forming. Recent images of the nebula have shed light on the poorly understood ejection of matter that accompanies the demise of sun-like stars. Objects like the Egg Nebula are relatively rare, because the evolutionary stage they are going through lasts only about 1,000 years. Only a few objects of this type have been identified, which makes this nebula important for study.