Ursa Major Constellation – The Great Bear of the Night Sky

In this article, we’ll be sharing with you everything you need to know about the constellation of Ursa Major, including how to find it, deep space objects contained within it, and how to use it to find other night sky objects more easily.

The Constellation of Ursa Major

Ursa Major is Latin for ‘the great bear’ and this easily recognized constellation was first cataloged by the Greek astronomer Ptolemy more than 2000 years ago.

In Greek mythology, the nymph named Callisto was chosen to be one of Artemis’s companions and was required to swear a vow of chastity to Artemis, the Greek goddess of hunting.

Zeus seduced Callisto (or the pair fell in love) and Callisto’s vow was broken. She bore Zeus a son named Arcas and was turned into a bear as punishment, either by Artemis for breaking her vow or by Hera (Zeus’s wife) for sleeping with her husband.

Fifteen years later, Arcas encountered a bear in the woods and not knowing it was his mother Callisto, attempted to kill it. Zeus intervened by sending a whirlwind to carry both Callisto and Arcas into the heavens. Callisto became the constellation Ursa Major and Arcas either became the constellation Boötes or the constellation Ursa Minor.

In another Greek myth, a prophecy foretold that the Titan Cronos would be overthrown by one of his children so he swallowed his children as they were born. Rhea (Zeus’s mother) smuggled an infant Zeus to the island of Crete to protect him from Cronos (Zeus’s father).

The nymphs Adrasteia and Ida nursed young Zeus and, after Zeus overthrew Cronus and freed his siblings, he honored Adrasteia and Ida by turning them into the constellations Ursa Major and Ursa Minor respectively.

To help you spot Ursa Major, here’s what SkySafari 6 shows (all sky charts on this page are courtesy of SkySafari 6). You can click on the image for a full size version.

The Great Bear of Ursa Major
The Great Bear of Ursa Major (click for full screen)

Ursa Major has an area of 1280 square degrees making it the 3rd largest of the 88 recognized constellations. Its asterism (a collection of stars that we recognize but is not a constellation), ‘The Big Dipper’, is one of the most recognizable asterisms in the sky.

The Big Dipper asterism in Ursa Major (the Plough in the UK)
The Big Dipper asterism in Ursa Major (the Plough in the UK)

As with all the constellations, Ursa Major covers a larger area of sky than just its asterism. The huge area of sky covered by Ursa Major is shown in the image below.

The whole of Ursa Major constellation's area shaded gray
The gray area shows the whole of Ursa Major constellation

In the next section discover how to find Ursa Major.

How To Find Ursa Major In The Night Sky

Ursa Major is the head of the Ursa Major family of constellations, which contains nine other constellations, including Boötes, Draco, and Ursa Minor.

Ursa Major is visible to observers at latitudes between +90° (the North Pole) and -30°. Northern Hemisphere observers can see Ursa Major all year long (it is a circumpolar constellation) while it’s only partially visible to northern Southern Hemisphere observers.

The constellation of Ursa Major is bordered by the constellations Boötes, Camelopardalis, Canes Venatici, Coma Berenices, Draco, Leo, Leo Minor, and Lynx.

The boundary constellations of Ursa Major
The boundary constellations of Ursa Major (click for full screen)

To find Ursa Major, do a naked-eye search for the Big Dipper in the northern sky. There are seven stars in the Big Dipper: Alkaid, Mizar, Alioth, Megrez, Dubhe, Merak, and Phecda (see image above).

To find Ursa Major’s exact position for your location on any night, use software such as Stellarium (free) or SkySafari 6.

Ursa Major’s Brightest Stars

Ursa Major contains several bright, notable stars. See the image below for their locations, and the detailed list below that of 25 stars brighter than magnitude 5.0.

Bright stars in Ursa Major
Bright stars in Ursa Major (click for full screen)

Alpha Ursae Majoris (Dubhe) – This double star is the second brightest star in Ursa Major and is one of the Big Dipper’s bowl stars. The 1.8 magnitude, orange giant, primary and 4.9 magnitude secondary components are 0.8 arcseconds apart, and unresolvable in smaller scopes.

Dubhe is 124 light-years away, making it the most distant of the Big Dipper stars. ‘Dubhe’ is derived from the Arabic phrase meaning ‘the back of the greater bear’.

Beta Ursae Majoris (Merak) – This 2.3 magnitude, white, main-sequence star is the fifth brightest star in Ursa Major and one of the Big Dipper’s bowl stars.

Merak is 79 light-years away and its traditional name is derived from the Arabic for ‘loins’ (of the bear).

Gamma Ursae Majoris (Phecda, Phekda, Phad) – This 2.4 magnitude, white, main-sequence star is the sixth brightest star in Ursa Major. Phecda is one of the Big Dipper’s bowl stars and is 84 light-years away.

All of its traditional names are derived from the Arabic for ‘thigh’ (of the Great Bear).

Delta Ursae Majoris (Megrez) – This double star is the seventh brightest star in Ursa Major. It’s the Big Dipper star that links the bowl to the handle and also links Ursa Major’s tail to its hindquarters.

The 3.3 magnitude, white, main-sequence primary, and 10.2 magnitude secondary component are 180 arcseconds apart (which is three arcminutes) and easily resolved in most backyard telescopes.

Megrez is 81 light-years away from us and its name is derived from the Arabic phrase meaning ‘root of the Great Bear’s tail’.

Epsilon Ursae Majoris (Alioth) – This double star is the brightest star in Ursa Major and the 31st brightest star in the night sky. The 1.8 magnitude, white, main-sequence primary and secondary components are 0.1 arcseconds apart and not resolvable in a regular telescope.

Alioth is one of the Big Dipper’s handle stars and is 81 light-years away. Its traditional name is a corrupted version of the Arabic phrase for ‘black horse’.

Zeta Ursae Majoris (Mizar)– This 2.2 magnitude double star is the fourth brightest star in Ursa Major. The primary and its 3.9 magnitude secondary component are 0.7 arcseconds apart.

Mizar shares its position as the Big Dipper’s central handle star with Alcor (below). Together, these are the first double star ever discovered by telescope. Both Mizar and Alcor are double stars in their own right, making this a lovely target for your telescope.

Mizar is 78 light-years away and this traditional name comes from the Arabic word for ‘groin’ or ‘girdle’.

80 Ursae Majoris (Alcor) – This is a double star. The 4.0 magnitude, white, main-sequence primary and 8.0 magnitude, dwarf, secondary components are 1.0 arcseconds apart but cannot be resolved by telescope.

Alcor is 81 light-years away and this traditional name comes from the Arabic word for ‘black horse’. Mizar and Alcor are 11.8 arcseconds apart and are known as the ‘horse and rider’ for their impressive binocular pairing.

Eta Ursae Majoris (Alkaid, Benetnash) – This 1.9 magnitude, blue-white, main-sequence star is the third brightest star in Ursa Major and the easternmost star in the Big Dipper’s handle.

Alkaid is 100 light-years away. Both its traditional names are Arabic, with Alkaid meaning ‘the leader’ and referring to the three handle stars of the Big Dipper. They were considered to be the three ‘daughters’ standing by the funeral bier that was the Big Dipper’s bowl.

Theta Ursae Majoris – This is a double or multiple star system. The 3.2 magnitude, yellow-white, subgiant, primary and 14.0 magnitude secondary components are 2.6 arcseconds apart. The secondary component has an unknown orbit and is beyond the reach of most backyard scopes.

Theta Ursae Majoris is 44 light-years away.

Iota Ursae Majoris (Talitha, Dnoces) – This is also a double star. The 3.1 magnitude, yellow-white, subgiant primary, and its 9.2 magnitude secondary component are 2.3 arcseconds apart.

The primary component (Iota UMa A) is a spectroscopic binary. The secondary component is a pair of dwarf stars (Iota UMa B and Iota UMa C). Talitha is 47.7 light-years away.

‘Talitha’ comes from the Arabic number three and ‘Dnoces’ is ‘second’ spelled backward after Apollo astronaut Edward H. White II. Fellow NASA astronaut Gus Grissom invented this name as a joke.

Iota Ursae Majoris and Kappa Ursae Majoris are one of three pairs of close stars that represent the feet of Ursa Major. These pairs are also known as the ‘leaps’ of a gazelle in Arabic.

Kappa Ursae Majoris (Talitha Australis) – This is a double star with a magnitude 3.6, white, main-sequence primary and 4.5 magnitude, white, main sequence, secondary component are 0.2 arcseconds apart. They are too close to be split in most telescopes.

The secondary has an unknown orbit. Kappa Ursae Majoris is 423 light-years away. Its traditional name comes from the Arabic word for ‘third’ and the Latin word for ‘southern’. Iota Ursae Majoris and Kappa Ursae Majoris are the ‘third leap’ of the gazelle.

Lambda Ursae Majoris (Tania Borealis, Alkafsah Borealis) – This magnitude 3.4, white subgiant is 134 light-years away.

Lambda Ursae Majoris and Mu Ursae Majoris mark another of Ursa Major’s feet and are the ‘second leap’ of the gazelle in Arabic. The traditional name ‘Tania Borealis’ comes from the Arabic word for ‘second’ and the Latin word for ‘northern’.

Mu Ursae Majoris (Tania Australis, Alkafzah Australis) – This magnitude 3.0, orange-red, giant is a semi-regular variable star whose magnitude varies from 2.99 to 3.33.

Mu Ursae Majoris is 250 light-years away. Lamba Ursae Majoris and Mu Ursae Majoris mark another of Ursa Major’s feet and are the ‘second leap’ of the gazelle in Arabic. The traditional name ‘Tania Australis’ comes from the Arabic word for ‘second’ and the Latin word for ‘southern’.

Nu Ursae Majoris (Alula Borealis) – This variable double star is 420 light-years away. The 3.5 magnitude, orange giant, primary and 10.1 magnitude secondary components are 7.8 arcseconds apart and make for a good observational pair.

Nu Ursae Majoris and Xi Ursae Majoris mark another of Ursa Major’s feet and are the ‘first leap’ of the gazelle in Arabic.  The traditional name ‘Alula Borealis’ comes from the Arabic word for ‘first’ and the Latin word for ‘northern’.

Xi Ursae Majoris (Alula Australis) – This variable double star is 24.6 light-years away. The 3.78 magnitude, yellow, main-sequence primary, and its 4.80 magnitude, yellow, main-sequence secondary component are 2.3 arcseconds apart. This makes a good challenge for a backyard scope.

Nu Ursae Majoris and Xi Ursae Majoris mark another of Ursa Major’s feet and are the ‘first leap’ of the gazelle in Arabic. The traditional name Alula Australis comes from the Arabic word for ‘first’ and the Latin word for ‘southern’.

Omicron Ursae Majoris (Muscida) – This is a variable double star whose secondary is too dim for most backyard scopes. The magnitude 3.4 yellow-white, giant primary and its 15.3 magnitude, red dwarf, secondary component are 7.1 arcseconds apart.

Omicron Ursae Majoris varies in magnitude from 3.3 to 3.8 over 358 days and is 185 light-years away. ‘Muscida’ is Latin for ‘muzzle’ and this star marks Ursa Major’s snout.

Pi2 Ursae Majoris (Museida) – This magnitude 4.6, orange star is 256 light-years away. Its energy output is 76 times the Sun’s.

Rho Ursae Majoris – This magnitude 4.8, orange-red giant is 315 light-years away.

Tau Ursae Majoris – This is a double star but the 4.6 magnitude, yellow-white giant primary and its 11.42 magnitude secondary component are too close to be separated visually. Tau Ursae Majoris is 126 light-years away.

Upsilon Ursae Majoris – This is a variable double star. The 3.8 magnitude, yellow-white subgiant primary, and the magnitude 11.3 secondary component are 12.1 arcseconds apart. The secondary component’s orbit is unknown.

Upsilon Ursae Majoris is 116 light-years away.

Phi Ursae Majoris – This is a double star. The 4.6 magnitude, white subgiant primary, and 5.4 magnitude secondary components are 0.5 arcseconds apart. The secondary component’s orbit is unknown.

Tau Ursae Majoris is 509 light-years away.

Chi Ursae Majoris (Al Kaphrah) – This magnitude 3.7, orange giant star is 184 light-years away.

Psi Ursae Majoris – This 3.00 magnitude, orange giant star is 145 light-years away. It’s 20.8 times the Sun’s diameter, 1.2 times the Sun’s mass, and 22% cooler than the Sun.

Omega Ursae Majoris – This 4.7 magnitude, blue-white, main-sequence star is 246 light-years away. It’s 3.3 times the Sun’s diameter, 2.7 times the Sun’s mass, and 1.6 times hotter than the Sun.

Star Hopping From Ursa Major

Ursa Major’s Big Dipper is the starting point for several star hops because it is in the sky all the time and full of bright, easily recognized stars.

Polaris – Draw an imaginary line from Merak to Dubhe (~5°). Extend this line ~28° to Polaris (see Ursa Minor), the brightest star in the Little Dipper asterism.

Arcturus – Extend the arc of the Big Dipper’s handle ~ 30° to Arcturus, the brightest star in the constellation Boötes. Gives the famous phrase ‘Arc to Arcturus and on to Spica’.

Finding Arcturus and Spica from Ursa Major
Finding Arcturus and Spica from Ursa Major

Spica – Extend the arc from Arcturus ~ 30° to Spica, the brightest star in the constellation Virgo.

Regulus  – Draw an imaginary line from Megrez to Phecda (~4°). Extend this line ~45° to Regulus, the brightest star in the constellation Leo and the bottom of the sickle asterism. The angular distance between Phecda and the middle of Leo is ~40°.

Capella – Draw an imaginary line from Megrez to Dubhe (~10°). Extend this line  ~49° to Capella, the brightest star in the constellation Auriga.

Pollux – Draw an imaginary line from Megrez to Merak (~10°). Extend this line  ~44° to Pollux, the brightest star in the constellation Gemini.

Car Caroli  – Draw an imaginary line from Alkaid to Denebola in Leo (~42°). Car Caroli (the brightest star in the constellation Canes Venatici) is roughly one-third of the way to Denebola (~14°).

Cassiopeia – Draw an imaginary line from any star in the Big Dipper’s handle through Polaris (in Ursa Minor) then double the length of this line to find the constellation Cassiopeia.

Summer Triangle – Draw an imaginary line from Phecda to Megrez (~4°). Extend this line ~60° to Vega (the brightest star in Cygnus) and Deneb (the brightest star in Lyra), at the top of the Summer Triangle asterism.

M81 & M82 – Draw an imaginary line from Phecda to Dubhe (~10°). Extend this line ~10° to M81 and M82 galaxies.

M109 – Draw an imaginary line from Merak to Phecda and extend this line ~38 arcminutes to M109 galaxy.

Objects To See Within Ursa Major

Ursa Major contains seven Messier objects and some other deep sky objects for small telescopes.

M40 (Winnecke 4)  – This double star system has a combined magnitude of 9.64 and an apparent size of 1.7 arcminutes. Its components are 1,900 and 550 light-years away and it’s at right ascension 12h 23m 15s and declination +57° 58’ 07”.

M81 (NGC 3031, Bode’s Nebula) – This spiral galaxy has a magnitude of 6.77 and an apparent size of 21.6 x 11.2 arcminutes. It’s 12 million light-years away and is at right ascension 09h 57m 15s and declination +68° 57’ 57”.

M82 (NGC 3034, Cigar Galaxy) – This spiral galaxy has a magnitude of 8.02 and an apparent size of 11.0 x 5.1 arcminutes. It’s 12 million light-years away and is at right ascension 09h 57m 36s and declination +69° 34’ 49”.

M97 (NGC 3587, Owl Nebula) – This planetary nebula has a magnitude of 9.80 and an apparent size of 3.4 x 3.3 arcminutes. It’s between 1,300 and 12,000 light-years away and is at right ascension 11h 15m 59s and declination +54° 54’ 09”.

M101 (NGC 5457, Pinwheel Galaxy) – This spiral galaxy has a magnitude of 7.77 and an apparent size of 24.0 x 23.1 arcminutes. It’s 27 million light-years away and is at right ascension 14h 3m 57s and declination +54° 14’ 55”.

M108 (NGC 3556) – This spiral galaxy has a magnitude of 9.96 and an apparent size of 4.0 x 1.7 arcminutes. It’s 45 million light-years away and is at right ascension 11h 12m 47s and declination +55° 33’ 38”.

M109 (NGC 3992) – This spiral galaxy has a magnitude of 9.62 and an apparent size of 8.1 x 5.6 arcminutes. It’s 84 million light-years away and is at right ascension 11h 58m 41s and declination +53° 15’ 29”.

NGC 5204 –  This spiral galaxy has a magnitude of 11.25 and an apparent size of 4.5 x 2.6 arcminutes. It’s 15 million light-years away and is at right ascension 13h 30m 24s and declination +58° 18’ 45”.

NGC 5474 – This spiral galaxy has a magnitude of 10.85 and an apparent size of 2.4 x 1.6 arcminutes. It’s 22 million light-years away and is at right ascension 14h 05m 46s and declination +55° 33’ 46”.

NGC 5585 – This spiral galaxy has a magnitude of 10.86 and an apparent size of 4.3 x 2.6 arcminutes. It’s 28 million light-years away and is at right ascension 14h 20m 29s and declination +56° 38’ 01”.

Summary

Ursa Major is a large constellation with many notable stars and deep sky objects.

It contains the Big Dipper asterism, which is one of the most recognizable sights in the night sky and it never sets below the horizon for most northern hemisphere observers, which is the starting point for many star hops.

Look north at any time of any night to begin your exploration of this constellation.


Written by Tanya C. Forde