Albireo is a celestial gem, a pair of stars colored indigo and gold, embedded in the glittering background of the Cygnus Star Cloud. Albireo may well be the most observed double star because of its stunning colors and easy-to-find location at the foot of the Northern Cross. When viewed with a telescope it readily resolves into a double star separated by 35", consisting of amber Albireo A at magnitude 3.1, and sapphire Albireo B at magnitude 5.1. It is not known whether the two components are orbiting each other as a binary system. If they are, their orbital period is at least 75,000 years.

The Albireo system is about 380 light years away. The brighter components of Albireo A are a stable helium-fusing giant of class K3, and a hydrogen-fusing main-sequence star of class B9. The K3 giant has a temperature of around 4400 K, a luminosity 950 times the Sun's, a radius 50 times solar, and a mass of about 5 times solar. Its close companion comes in at 11,000 K, 100 solar luminosities, and 3.2 solar masses.

Imaging Data

Date: 8-23-2011

Location : Sudbury, Massachusetts

Optics : TV-85 Apo Refractor

Filter(s) : Astronomik CLS-CCD

Mount : Vixen GP Mount

Autoguiding : None

Camera : Canon EOS 1000D Astro-modified

Exposure info : 10 x 9 second Exposures @ISO 400

Total Exposure : 1.5 minutes