Struve 2816 and 2819: Triple and Double Stars in Cepheus
November 2012 :
There’s something hypnotic about a double star – two gleaming points of light shining bravely through the surrounding darkness. A triple star is even more mesmerizing. Place a double star and triple star in the same eyepiece field, and the visual effect is stunning. This is what greets the eye when you view the triple/double star combo Struve 2816 and Struve 2819.
Struve 2816 and Struve 2819 are among the 3000-plus double and multiple stars catalogued by the Russian astronomer F.G.W. Struve in the 1820s and 30s. They lie in Cepheus, about a degree south of mu (µ) Cephei (Herschel’s “Garnet Star”).
The triple star Struve 2816 consists of a magnitude 5.7 primary flanked by two 7.5 magnitude stars at distances of 12 and 20 arc-seconds. Just 12 arc-minutes away is Struve 2916 - a magnitude 7.5 and 8.5 duo, separated by 13 arc-seconds.
Struve 2816 and Struve 2819 appear together even in the eyepiece field of large-aperture Dobs, but I find the most eye-pleasing views are through small-aperture scopes. Large instruments clutter up the field with a distracting number of faint background stars. Struve 2816 and Struve 2819 are part of the wide open cluster Trumpler 37 which, in turn, is immersed in the huge emission nebula IC 1396.
The accompanying finder chart/ photograph and eyepiece sketch come from the Starsplitters website (http://bestdoubles.wordpress.com), a wonderful collaboration by amateur astronomers John Nanson and Greg Stone. It’s a must-visit blog for the double star enthusiast!
