Dark Nebula in Aquila

A very dense section of the Milky Way passes through Aqula, the eagle. The blue semicircle at the bottom of this image is nothing of significance--it is simply lens flare from the bright first-magnitude star Altair, which is just outside the frame. Altair marks the head of the eagle, and about 2 degrees to the northwest is the third-magnitude star Tarazed. Look about another 2 degrees to the west, and you will find a dark nebula that has a rough E shape, called Barnard's E.

The astronomer E. E. Barnard cataloged dark nebulae throughout the sky. They are areas of gas and dust that block the light of the stars behind them, so they appear as relatively empty patches of sky. Dark nebulae are a challenge to see visually. They show up better in long-duration photographs.

Image details:  12 images, each 90 seconds at ISO 1600, taken with a Canon 400D camera at a focal length of 200 mm.

August 2009