IC 59-IC 63

IC59 (the blue nebula) and IC63 (the red part) are good examples of a reflection nebula and an emission nebula.
The blue reflection nebula is illuminated by the light of Gamma Cassiopeia (the center star in the W shape of Cassiopeia).

The emission nebula consists of ionised hydrogen and therefore appears red in this image.
The reflection nebula lights up by the starlight of Gamma Cassiopeia. The starlight scatters off dust clouds which causes the blue reflection.

Both nebulae can be found in the center of the constellation Cassiopeia and lie at a distance of about 600 light years.