Albireo, beloved double star

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Albireo, beloved double star
Bruce McClure in ASTRONOMY ESSENTIALS | BRIGHTEST STARS | August 4, 2019

Albireo is known best for the striking color contrast between its two stars – the brighter gold star and the dimmer blue star.

Albireo, one star blue and the other golden. Photo via Tom Wildoner.​

Albireo – also called Beta Cygni – isn’t the brightest star in the sky. It looks like an ordinary single star to the eye. But peer at it through a telescope, and you’ll learn why stargazers love Albireo. With a telescope, you’ll easily see Albireo as a beautiful double star, with the brighter star gold and the dimmer star blue.

How can you see Albireo as two stars? They are best viewed at 30X (“30 power” or a magnification of 30). Unless you have exceedingly powerful binoculars, mounted on a tripod, binoculars won’t show you Albireo as two stars, but any small telescope will. When you do see Albireo as two stars, notice the striking color contrast between the two.

How can you spot Albireo in the night sky? It’s easy to find, if you can locate Cygnus the Swan. Cygnus has an easy-to-recognize shape, that of a cross, and the constellation is also known as the Northern Cross. The brightest star in Cygnus, called Deneb, marks the head of the Cross or the Tail of the Swan. Albireo marks the base of the Cross or the Head of Cygnus.

The constellation Cygnus the Swan. The bright star Deneb is in the Tail of Cygnus,
while Albireo is at the Head of the Swan. Albireo represents the Swan’s Beak or Eye.
Image via Constellation of Words.​

The two stars of Albireo constitute a true binary star system. In other words, its two stars aren’t merely a chance alignment as seen from Earth. Instead, they revolve around a common center of mass.