The APOD for Aug. 30, 2005, has this: Explanation: Sometimes, even a small telescope can help unlock a hidden beauty of the heavens. Such is the case of the bright double star Albireo. Seen at even slight magnification, Albireo unfolds from a bright single point into a beautiful double star of strikingly different colors. At 380 light years distant, the two bright stars of Albireo are comparatively far from each other and take about 75,000 years to complete a single orbit. The brighter yellow star is itself a binary star system, but too close together to be resolved even with a telescope. Albireo, pictured above, is the fifth brightest star system toward the constellation of the Swan (Cygnus) and easily visible to the unaided eye. -- If they take 75,000 years for one go-round, we can't see the motion. This makes it seem that NASA has concluded that they are a true physical binary, however. -- Joe --- On Sun, 5/17/09, M Wilson <astro_outwest@yahoo.com> wrote: From: M Wilson <astro_outwest@yahoo.com> Subject: [Utah-astronomy] Albireo: a double star? To: "Utah astronomy blog" <utah-astronomy@mailman.xmission.com> Date: Sunday, May 17, 2009, 12:15 AM I found this a few years ago in the 1978 edition of Burnham's (Burnbaum's) Celestial Handbook Vol. II, page 754, third paragraph:   "Albireo is believed to be a physical pair, although no evidence of ortibal motion has been detected since the first observations of F.G.W. Struve in 1832."   Most of us, including myself, have been telling the public for years that the two were gravitationally bound.  Looks like the proof is lacking or is Burnham's is out-of-date?       _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com