Nebula of stellar evolution
Adam Block, astrophotographer and astronomy educator with the University of Arizona's Mt. Lemmon SkyCenter, selected his own image of nebula SH2-239 as his favorite. He writes: "[I] suspect you will not find...a higher resolution (full) color image of this particular nebula. The important idea to consider is that this object is certainly not unknown. This field represents the earliest stages of stellar evolution — the birth place of stars, and it is studied intensively by astronomers."