Ursa Maior

English name Great Bear, Plough or Big Dipper

Major
stars alpha Ursae Maioris Dubhe magn. 2,0 RA: 11h 03m 43.73s Dec: +61° 45' 03.3"
beta Ursae Maioris Merak magn. 2,4 RA: 11h 01m 50.47s Dec: +56° 22' 56.5"
gamma Ursae Maioris Phecda magn. 2,5 RA: 11h 53m 49.81s Dec: +53° 41' 41.1"
delta Ursae Maioris Megrez magn. 3,4 RA: 12h 15m 25.54s Dec: +57° 01' 57.3"
epsilon Ursae Maioris Alioth magn. 1,7 RA: 12h 54m 01.73s Dec: +55° 57' 35.6"
zeta Ursae Maioris Mizar magn. 2,4 RA: 13h 23m 55.52s Dec: +54° 55' 31.4"
eta Ursae Maioris Alkaid magn. 1,9 RA: 13h 47m 32.47s Dec: +49° 18' 48.1"
theta Ursae Maioris magn. 3,3 RA: 09h 32m 51.64s Dec: +51° 40' 39.5"
iota Ursae Maioris Talitha magn. 3,1 RA: 08h 59m 12.55s Dec: +48° 02' 30.3"
lambda Ursae Maioris Tania Borealis magn. 3,5 RA: 10h 17m 05.83s Dec: +42° 54' 51.9"
my Ursae Maioris Tania Australis magn. 3,2 RA: 10h 22m 19.76s Dec: +41° 29' 58.2"
omicron Ursae Maioris Muscida magn. 3,5 RA: 08h 30m 15.92s Dec: +60° 43' 05.7"
psi Ursae Maioris magn. 3,1 RA: 11h 09m 39.80s Dec: +44° 29' 54.7"

Description Important constellation of the northern hemisphere, third in order of extension, after Hydra and Virgo.
Thanks to a group of seven stars (from alpha to eta Ursae Maioris), that draw the figure known as Plough or Big Dipper, Ursa Maior is perhaps the most famous and well known constellation of the whole sky. The first two stars of the dipper, Dubhe and Merak, are useful to find the North Pole, since the line that contains them directs toward the Polaris, in Ursa Minor.
The second star of the beam, Mizar, is a multiple star. To the naked eye we succeed in seeing a companion of fourth magnitude, Alcor; and with a small telescope we can perceive another star of fourth magnitude, near Mizar. And since every of these three stars is a double, as spectroscopic observations reveal, this is a system with well six stars.
Another interesting double star is xi Ursae Maioris, in the southern zone of the constellation, near Leo: it is a couple of yellow stars which rotate round each other with a 60-year period.
M81 The constellation of Ursa Maior contains a pair of remarkable galaxies: M81, a beautiful spiral galaxy of eighth magnitude (reproduced here on the right); and M101, on the border with Bootes, another spiral galaxy of ninth magnitude.

Mythology
and history According to Eratostenes and Ovid, the constellation represents the animal into which was changed Callisto, mother of Arcas (see the mythology of Bootes).
Aratus, instead, affirms that the constellation must be identified with one of the two nymphs who raised the new-born Zeus: her name was Adrastea, while the other one was Ida, represented by Ursa Minor. Aratus, however, doesn't explain why these nymphs were changed into she-bears.
An enigma that unites the two heavenly she-bears is representes by the long tails, which have nothing in common with the shorter tails of the true bears. Thomas Hood, an English astronomer of the XVI century, ironically justified this detail by saying that such extremities grew longer when Zeus lifted the she-bears to put them in the sky, just grasping their tails.

English name	Great Bear, Plough or Big Dipper

Major stars	alpha Ursae Maioris	Dubhe	magn. 2,0	RA: 11h 03m 43.73s	Dec: +61° 45' 03.3"
	beta Ursae Maioris	Merak	magn. 2,4	RA: 11h 01m 50.47s	Dec: +56° 22' 56.5"
	gamma Ursae Maioris	Phecda	magn. 2,5	RA: 11h 53m 49.81s	Dec: +53° 41' 41.1"
	delta Ursae Maioris	Megrez	magn. 3,4	RA: 12h 15m 25.54s	Dec: +57° 01' 57.3"
	epsilon Ursae Maioris	Alioth	magn. 1,7	RA: 12h 54m 01.73s	Dec: +55° 57' 35.6"
	zeta Ursae Maioris	Mizar	magn. 2,4	RA: 13h 23m 55.52s	Dec: +54° 55' 31.4"
	eta Ursae Maioris	Alkaid	magn. 1,9	RA: 13h 47m 32.47s	Dec: +49° 18' 48.1"
	theta Ursae Maioris		magn. 3,3	RA: 09h 32m 51.64s	Dec: +51° 40' 39.5"
	iota Ursae Maioris	Talitha	magn. 3,1	RA: 08h 59m 12.55s	Dec: +48° 02' 30.3"
	lambda Ursae Maioris	Tania Borealis	magn. 3,5	RA: 10h 17m 05.83s	Dec: +42° 54' 51.9"
	my Ursae Maioris	Tania Australis	magn. 3,2	RA: 10h 22m 19.76s	Dec: +41° 29' 58.2"
	omicron Ursae Maioris	Muscida	magn. 3,5	RA: 08h 30m 15.92s	Dec: +60° 43' 05.7"
	psi Ursae Maioris		magn. 3,1	RA: 11h 09m 39.80s	Dec: +44° 29' 54.7"

Description	Important constellation of the northern hemisphere, third in order of extension, after Hydra and Virgo. Thanks to a group of seven stars (from alpha to eta Ursae Maioris), that draw the figure known as Plough or Big Dipper, Ursa Maior is perhaps the most famous and well known constellation of the whole sky. The first two stars of the dipper, Dubhe and Merak, are useful to find the North Pole, since the line that contains them directs toward the Polaris, in Ursa Minor. The second star of the beam, Mizar, is a multiple star. To the naked eye we succeed in seeing a companion of fourth magnitude, Alcor; and with a small telescope we can perceive another star of fourth magnitude, near Mizar. And since every of these three stars is a double, as spectroscopic observations reveal, this is a system with well six stars. Another interesting double star is xi Ursae Maioris, in the southern zone of the constellation, near Leo: it is a couple of yellow stars which rotate round each other with a 60-year period. The constellation of Ursa Maior contains a pair of remarkable galaxies: M81, a beautiful spiral galaxy of eighth magnitude (reproduced here on the right); and M101, on the border with Bootes, another spiral galaxy of ninth magnitude.

Mythology and history	According to Eratostenes and Ovid, the constellation represents the animal into which was changed Callisto, mother of Arcas (see the mythology of Bootes). Aratus, instead, affirms that the constellation must be identified with one of the two nymphs who raised the new-born Zeus: her name was Adrastea, while the other one was Ida, represented by Ursa Minor. Aratus, however, doesn't explain why these nymphs were changed into she-bears. An enigma that unites the two heavenly she-bears is representes by the long tails, which have nothing in common with the shorter tails of the true bears. Thomas Hood, an English astronomer of the XVI century, ironically justified this detail by saying that such extremities grew longer when Zeus lifted the she-bears to put them in the sky, just grasping their tails.

Ursa Maior

Back to constellations page.