The Big Dipper (US, Canada) or the Plough (UK, Ireland)[1][2] is a large asterism consisting of seven bright stars of the constellation Ursa Major;[3][4][5][6] six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" or "body" and three define a "handle" or "head". It is recognized as a distinct grouping in many cultures. The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper (Little Bear), can be located by extending an imaginary line through the front two stars of the asterism, Merak (β) and Dubhe (α). This makes it useful in celestial navigation.
- ^ Stern, David P. (23 April 2008). "Finding the Pole Star". Goddard Space Flight Center. Archived from the original on 5 March 2016. Retrieved 31 August 2013.
- ^ Rao, Joe (9 May 2008). "Doorstep Astronomy: See the Big Dipper". space.com. Retrieved 31 August 2013.
- ^ Holbrook, J. C.; Baleisis, Audra (2008). "Naked-eye Astronomy for Cultural Astronomers". African Cultural Astronomy. Astrophysics and Space Science Proceedings. pp. 53–75. Bibcode:2008ASSP....6...53H. doi:10.1007/978-1-4020-6639-9_5. ISBN 978-1-4020-6638-2.
- ^ Olson, R. J. M.; Pasachoff, J. M. (1992). "The 1816 Solar Eclipse and the Comet 1811I in Linnell's Astronomical Album". Journal for the History of Astronomy. 23: 121. Bibcode:1992JHA....23..121O. doi:10.1177/002182869202300204. S2CID 125474099.
- ^ John C. Barentine (4 April 2016). Uncharted Constellations: Asterisms, Single-Source and Rebrands. Springer. pp. 16–. ISBN 978-3-319-27619-9.
- ^ Nemiroff, R.; Bonnell, J., eds. (21 April 2013). "Big Dipper". Astronomy Picture of the Day. NASA.