Nevenka Blagović & Miroslav Horvat
Location of Photo:
Kamenjak viewpoint, Vrana lake, Croatia
Date/Time of photo:
5th July 2019
Optical system: SW ED80, SW 0.85 FF/FR, Camera: QHY8c, Mount: SW EQ6Pro, Guiding: SW 9x50 finderguider with QHY5L-IIC, Exposure: 11 x 15 min, Gain 4%, Offset 123, dark, flat, Software: SGpro, Pixinsight 1.8, PS CC 2017
Collinder 399 is a random grouping of stars located in the constellation Vulpecula near the border with Sagitta. The members of the star cluster form an asterism which has given rise to its name as the Coathanger. The asterism is made up of 10 stars ranging from 5th to 7th magnitude which form the conspicuous "coathanger", a straight line of 6 stars with a "hook" of 4 stars on the south side. An additional 30 or so fainter stars are sometimes considered to be associated as well. Under a dark sky, the Coathanger can be seen with the naked eye as an unresolved patch of light; binoculars or a telescope at very low power are usually needed in order to view the "coathanger" asterism. It is best found by slowly sweeping across the Milky Way along an imaginary line from the bright star Altair toward the even brighter star Vega. About one third of the way toward Vega, the Coathanger should be spotted easily against a darker region of the Milky Way. The asterism is best seen in July–August and north of 20° north latitude it is displayed upside down when it is at its highest point. South of this latitude it is shown upright as the 'hanger' is south of the line of 6 stars. The asterism and its immediate surroundings are a useful gauge for determining the faintest stars visible in a small telescope as there are a wide range of stellar magnitudes within the cluster easily viewed in one small location of the sky.