Double star in Cygnus
Albireo is one of the best-known double stars in the sky. To the naked eye, it appears as a single star that marks the head of Cygnus, the Swan. Through even a small telescope, the two stars are easy to separate, and their orange and blue colors make them a beautful pair. Through a large telescope, the two stars are so bright that their colors may be washed out. When I show this double star to people at public observing sessions, I tell them to try putting the eyepiece slightly out of focus, which spreads the light of each star over a wider area and makes the colors more obvious.
This pair is about 400 light years away.
Image details: 10 exposures, each 10 seconds at ISO 1600, taken with a Canon 400D camera through a Meade 12” telescope at f/10.
September 2008