Messier 45 (M45), also known as the Pleiades or Seven Sisters, is a bright open star cluster located in the constellation Taurus,
The Pleiades cluster has an apparent magnitude of 1.6 and lies at an average distance of 444 light years from Earth. The cluster is also known as Melotte 22. It does not have an NGC designation.
Messier 45 contains a number of hot, blue, extremely luminous B-type stars and is one of the nearest star clusters to Earth. It is the easiest object of its kind to see without binoculars. M45 has a core radius of 8 light years and its tidal radius extends to about 43 light years. The cluster is home to more than 1,000 confirmed members, but only a handful of these stars are visible to the naked eye. The total mass of M45 is estimated at about 800 solar masses.
The Pleiades cluster occupies an area of 110 arc minutes, about four times the apparent diameter of the full Moon. Up to 14 stars are visible without binoculars in good conditions, with clear skies and no light pollution. The best time of year to observe M45 from northern latitudes is during the winter months, when Taurus constellation
rises high in the sky. Because of the cluster’s apparent size, the best way to see it is through binoculars and small or wide field telescopes. Higher magnification is only recommended for studying individual stars.
The names of the nine brightest stars in M45 are taken from Greek mythology and they represent the Pleiades, the Seven Sisters – Sterope, Electra, Merope, Maia, Celaeno, Taygeta, and Alcyone – and their parents, Pleione and Atlas.
Mount: Paramount MYT unguided
Scope: Takahashi FSQ106 EDXIII
Location: Southern Arizona