Dubhe
Designations
- Bayer: α UMa
- Flamsteed: 50 UMa
- Hipparchos: HIP 54061
Data
- Constellation: Ursa Major
- Apparent Magnitude: 1.79
- Right Ascension (J2000): 11h03m41.06s
- Declination (J2000): +61°15'16".3
- Colour Index (B-V): 1.07
- Distance: 122.89±2.22ly
Description
Situated at the spout of the Big Dipper, Dubhe is of special importance to amateur astronomers as it is one of the Pointers, an asterism used to locate Polaris (α UMi) and thus the North Celestial Pole as well. A line drawn from Merak through Dubhe and continued northwards will eventually arrive near Polaris. To remember this usage, use the mnemonic, "from Merak, we smoke a Dubhe on the way to Polaris!" Along with Merak (β UMa) this star marked one of Hyginus's plough-oxen pulling the cart of Boötes, represented by the other five stars of the Big Dipper.
Nomenclature
Dubhe
According to Kunitzsch and Smart (2006), the name was applied in medieval times from al-Dubb , 'the bear', an abbreviation the Arabic term for the constellation, al-Dubb al-Akbar, 'the great bear'. The abbreviation was bastardised into Latin as Edubh, which in turn was corrupted my misplacing the e at the end of the word, creating the modern form of Dubhe.