The Sky at Night

The dominating constellation of summer nights is surely Cygnus, the Swan. The great celestial bird apparently flies through the Milky Way, its long neck and outstretched wings delineated by bright stars in a cross formation; indeed, it is sometimes called "the northern cross". This part of the sky is strewn with moderately bright stars within the formal boundaries of Cygnus, though not part of the cross itself. Cygnus rewards a sweep with binoculars to penetrate even more deeply into the riches of the Milky Way than the eye alone can. Albireo, second brightest star of Cygnus, is widely cited as the most glorious of double stars. Its distinctive feature is the colour contrast between the pair. One is a third-magnitude yellow star; its fifth-magnitude companion has a bluish hue. Albireo appears as a single star to the naked eye, but is easily resolved by binoculars or a small telescope.

Jacqueline Mitton