We consider independent methods of determining ion abundances for emission nebulae, comparing ion emission measures with column densities derived from resonance absorption lines viewed against the ...

This Hubble mosaic is the highest resolution image ever made of the entire Crab Nebula, which is located 6,500 light-years away. These opaque, dark knots of gas and dust called "Bok globules" are ...

Little Dumbbell Nebula (also known as Messier 76, M76, or NGC 650/651) located 3,400 light-years away in the northern circumpolar constellation Perseus. It is classified as a planetary nebula, an ...

The red nebula is a merger of two massive emission nebulae. The nebula at the head position, NGC2327, and the nebula that appears to be the wings, IC2177, take on the shape of a seagull or duck.