Optical/IR Composite of Orion

The H_2 image of Allen and Burton (1993) [red], combined with the new HST [S II] + [O I] image [green] and the HST H-alpha image [blue]. The red halo around the stars is an artifact caused by the poorer spatial resolution of the ground-based images. Arrows denote proper motions over the last 400 years. The major HH object groups are marked in the figure.