The Coathanger (Brocchi's Cluster)

The cooler summer nights bring out the ghostly flow of the Mily Way in the night sky, with some of the brightest stars as the main actors – Deneb, Vega and Altair. The Summer Triangle rules the sky for months in a row, hanged high above our heads. Once we start zooming in with our binoculars and telescopes, the noisy, crowded galactic background begins to split into its constituents – star clouds, star clusters, dust lanes and various nebulae.
Caught between the never-ending fight between the Eagle (Aquila) and the Swan (Cygnus) sits a well-known asterism of 10 stars called the Coathanger, of which 6 stars are almost perfectly aligned. Its catalogue name is Collinder 399 and can be found at the border between 2 small constellations, Vulpecula and Sagitta. Considered since its early sightings in the 10th century to be a star cluster, in 1997, the Hipparcos mission finally concluded that the Coathanger is a mere accidental alignment of unrelated stars.
It was first described by the Persian astronomer Al Sufi in his “Book of Fixed Stars” in 964. In the 17th century, it was independently rediscovered by the Italian astronomer G. B. Hodierna. In the 1920s, Dalmero Francis Brocchi, an amateur astronomer and chart maker for the American Association of Variable Star Observers (AAVSO), created a map of the stars for use in calibrating photometers. In 1931, Swedish astronomer Per Collinder listed it in his catalogue of open clusters.
The main stars are 4 Vulpeculae and 5 Vulpeculae, with apparent magnitudes of +5,2 and +5,6. These 2 are also the closest to us, at around 240 light-years, and they are also quite close to each other (20 light-years. Most of the other members are A and B-type giants that sit between 353 and 1735 light-years away.
West of the 6-star alignment sits a subtle open cluster, NGC 6802, which is more than 4.400 light-years away. It contains more than 70 stars and it has an elongated shape.