The Orion Nebula In The Daytime

NOV 10, 2010

The Orion Nebula is one of the brightest nebulae in the night sky. But, even so, it is not bright by daytime standards. However, the light we receive from the Orion Nebula is very special. The stars in the nebula are, of course, just stars. Nothing special there. But, the glowing gas that makes the nebula interesting produces light of only a few very specific wavelengths. Most of it is so-called hydrogen-alpha (Ha) light, which is a deep red light having wavelength equal to 6563 Angstroms. By using a filter that blocks out all of the light except for those wavelengths in a very narrow band around 6563 Angstroms, it is possible to cut out almost all of the light pollution and take a beautiful picture of the nebula. Amazingly, this trick of using a narrow-band filter works so well one can take a picture of Orion in the daytime. I took the picture shown at right exactly at the moment of sunrise on September 9, 2007. Click on the picture to see more pictures taken several minutes after sunrise as well as a picture of the Sun reflecting off my neighbors window.

Narrowband Ha filters can be purchased from a few different sources including Astrodon, Astronomik, and Custom Scientific.