Collinder 442

Collinder 442 (NGC 7142) is an old, faint open cluster in the constellation Cepheus, located approximately half a degree from NGC 7129 (Collinder 441). Its distance is estimated to be between 6,200 and 7,500 light-years. The cluster is known as one of the oldest open clusters; its color-magnitude diagram bears a strong resemblance to those of M67 and NGC 188. Its age is estimated at 3 to 4 billion years. Its metallicity and age were found to be indistinguishable from those of M67. The cluster contains five "red clump" giants, two stars on the asymptotic giant branch, and four "blue stragglers", a remarkable feature for such an old cluster.