More M42, Lowell Observatory -

The innermost part of the Orion Nebula M42 taken in a filter

emphasizing H-alpha emission. This shows the intricate structure of the

nebula as revealed by gas. The four bright stars constitute the

Trapezium; most of the ionizing radiation for this part of the

nebula comes from the hottest of these stars.

The same region of the Orion Nebula, now in a filter that passes

essentially pure continuum radiation. Fainter members of the

associated star cluster can be seen now free of the strong emission seen

at H-alpha; much of the nebular structure seen in this filter is from

starlight scattered by dust grains. Both Orion images were taken with a

Loral CCD at the Lowell Observatory 1.1m telescope.

Credit: Bill Keel, University of Alabama; taken from his