The Coathanger Asterism, Collinder 399
Sketch and Details by Rony De Laet
Binocular Icon 21 : The Coathanger.
One of the highlights of a summer binocular tour of the heavens is Collinder 399. It is a loose group of stars, which is visible to the naked eye. The first written observations of this cluster go back to AD 946, when the Persian astronomer Al Sufi described Cr 399 as a little cloud. Cr 399 can be found between Cygnus and Aquila, a mere 5° west of Sagitta. From my backyard, I can detect a trio of stars in a little fuzzy spot. With a pair of binoculars, the cluster shows a real coathanger! Point the bino’s at Albireo and draw a line to Anser (Alpha Vulpeculae). Continue in the same direction until Answer nears the northern border of the field of view. Cr 399 should appear at the southern edge of the field stop of the binoculars. The Coathanger is an amazing sight, even under light polluted skies. The cluster consists of 10 bright stars. Six of them form the 1.4° long bar of the hanger, in a perfect east to west orientation. Cr 399 is believed to be a chance alignment and not a true cluster.
Site : Bekkevoort, Belgium
Date : June 10, 2008
Time : around 00.30UT
Binoculars : Bresser 8×56
Filter : none
Mount : Trico Machine Sky Window
Seeing : 2,5/5
Transp. : 3.5/5
Nelm : around 5.3
Sketch Orientation : N up, W right.
Digital sketch made with Photo Paint, based on a raw pencil sketch.