Pleiades-the star cluster in the Taurus constellation

The Pleiades star cluster, also known as the Seven Sisters and Messier 45, is a conspicuous object in the night sky with a prominent place in ancient mythology. The cluster contains hundreds of stars, of which only a handful are commonly visible to the unaided eye. The stars in the Pleiades are thought to have formed together around 100 million years ago, making them 1/50th the age of our sun, and they lie some 130 parsecs (425 light years) away. From our perspective they appear in the constellation of Taurus, with approximate celestial coordinates of 3 hours 47 minutes right ascension and +24 degrees declination. For northern hemisphere viewers, the cluster is above and to the right of Orion the Hunter as one faces south, and it transits -- reaches its highest point in the sky, midway between rising and setting -- around 4am in September, midnight in November, and 8pm in January.

The image at the top of the page shows the central part of the cluster, where the brightest stars are found. This color photograph was taken in three filters, each exposed for about a half-hour, by David Malin with the UK Schmidt Telescope. The image is roughly 1.5 degrees wide, or three times the angular diameter of the moon. North is up and east is to the left. The cluster distance of 130 parsecs makes the physical width of the picture about 3.4 parsecs (11 light years); the cluster itself has a width perhaps 10 times greater, but most of the bright stars are found within one or two degrees of the core.