It appears that there's a very popular misconception on the web that Albireo A & B are a binary star system. And even more interesting that those who disagree, and call them a mere double star ignore any "binary" terminology in this beak of Cynus the Swan. I've searched everywhere with google image with the added keyword "binary" and the resulting photos are always the yellow and blue stars.
Last night, there was night observing at the roof of Columbia University's astronomy building. I asked if they were binary, one said double star, another thought to be binary. And the discussion on how the A and Be stars may be binary if one doesn't mind the possible thousands of years per orbital.
Finding the discussion intriguing, I searched the web immediately when I got home, a little after midnight, thanks to Wikipedia, the yellow star, Albireo A, is known to be a binary star itself. One quote: "In 1976, component A was itself discovered to be a binary star, using speckle interferometry and the 2.1-meter telescope at the Kitt Peak National Observatory." (Speckle interferometric measurements of binary stars. VI, H. A. McAlister and E. M. Hendry, Astrophysical Journal Supplement Series 48 (March 1982), pp. 273–278.)
And another interesting fact is the fact that the current angular separation of roughly 0.4 arcseconds makes it hard to be visually observed with instruments smaller than 20". Where can you get a 20" telescope? The two larger ones in Columbia University's observatories are only 14" and 12", and mine's only 6". Not to mention the city light pollution and a construction which will block the west view...poor Pupin's astrolab.
With the 0.4 arcseconds information, I examined it with Stellarium, my favorite skymap FREEWARE. And at first, I just thought maybe Stellarium isn't that sophisticated enough as I was getting tired of zooming in. But when it reached 0.2 arcseconds, WOW, the big bright star which was filling my entire screen actually splits into two (Labelling them as HIP95947 A and 95947 C)! Amazing indeed!!!