NGC 188, is an ancient open cluster located in the constellation of Cepheus.

It is located 4 degrees from Polaris, Alpha Ursae Minoris.

NGC 188 subtends an apparent angle of 15 arcminutes and shines at an apparent magnitude of 8.1. It contains 120 stars ranging from 12th to 17th magnitude. The ten brightest stars are spectral type G8 yellow-giants of magnitude 12 to 14.

NGC 188 is located 5,700 light-years away. At that distance its true size would be 23 light-years in diameter.

NGC 188 is believed to be one of the older open clusters known with an estimated age of some 6 billion years. It is thought that NGC 188 has managed to stay together as a cluster this long because of its location high above the galactic plane.

Old open clusters are usually dominated by old red stars. The stars in NGC 188, however, also include a small population of blue stars. These "blue stragglers" were a bit of a mystery as blue stars are usually young. In 2011 Aaron Geller and Robert Mathieu used the WIYN 3.5 meter telescope to study these stars. They found that they probably formed from mass transfers or mergers in binary star systems in the cluster.

NGC 188 was discovered by John Herschel in 1831.

North is to the top in the above image.

NGC 188 Catalogs: NGC 188 Object Type: Open Cluster Magnitude: 8.1v Size: 15' Constellation: Cepheus Image Field Centered At: RA: 00h 46m 36s Dec: +85° 15' 05"