Brocchi's Cluster (also known as Collinder 399, Cr 399 or Al Sufi's Cluster) is a asterism of six stars in an apparent row, across 1.3° of the night sky and four others, in the south of the constellation Vulpecula, thus near Sagitta. Its nickname is the Coathanger. None of these ten stars are believed to be much gravitationally associated, so not a star cluster, a fact not known until 1997. An additional 30 or so much fainter stars to terrestrial observers are sometimes considered to be associated. History 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. Status The status of this group as a star cluster has changed in recent years. The group was considered to be a cluster for most of the 20th century. Looking at better, but imprecise metrics, a study in 1970 said that six of the brightest stars formed a cluster, the fainter four did not. Several independent studies since 1998 have determined that the stars are not a true cluster at all, but rather relatively near Milky Way stars on a close angular alignment. These recent studies are mostly rooted on improved measurements of parallax and proper motion from the Hipparcos satellite, picking up minute changes in angle as against other stars as it orbits the sun (with the Earth). This data was first published in 1997 and has been enhanced by subsequent orbits and cross-referencing with other readings. 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 much fainter stars to terrestrial observers are sometimes considered to be associated. Under a dark sky, the coathanger can be seen with the naked eye as an unresolved patch of light; binoculars, zoom camera or a telescope at very low power are usually needed to view this asterism. It is best found by