The Plough

The Big Dipper

GenitiveUrsae Majoris
Right Ascension11h02 to 13h48
Declination+49° 18' to +61° 45'
Area (sq deg)383
Brightest StarAlioth
Optimum VisibilityMarch/April (Usually visible from northern latitudes)
Map of the Plough

A group of seven prominent stars in Ursa Major (from left to right: Benetnash, Mizar, Alioth, Megrez, Phekda, Merak and Dubhe). Together, they form probably the most recognisable star group in the sky. Seen from northern latitudes, the Plough never sets, but swings slowly around the Pole Star every night of the year.

Like all constellations, the apparent pattern of the Plough is in reality a line-of-sight effect, and the seven famous stars in fact lie at quite different distances from Earth. The closest is Mizar, 78 light years away, while the farthest is Dubhe, 123 light years distant. Seen from a location more than a few light years from the Solar System, the arrangement of this group of stars would be noticeably different (and indeed may not form a recognisable pattern at all).


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