Ursa Major: Constellation Guide
Ursa Major, commonly referred to as the Big Dipper (we’ll explain later why this name isn’t absolutely correct), is the most recognizable constellation in the Northern Hemisphere. It was listed by the Greek astronomer Claudius Ptolemy in his Almagest more than 2,000 years ago, and now it’s known worldwide. Ursa Major is not only one of the easiest constellations to find; it also helps you locate other stars and constellations.
Ursa Major facts
- Name: Ursa Major (the Great Bear)
- Abbreviation: UMa
- Asterism: The Big Dipper
- Size: 1,280 sq. deg. (3rd largest constellation)
- Right ascension: 10,67 h
- Declination: +55.54°
- Visible between: 90°N — 30°S
- Celestial Hemisphere: Northern
- Brightest Star: Alioth (Epsilon Ursae Majoris)
- Main Stars: 19
- Messier DSO: 7
- Bordering constellations: Boötes, Camelopardalis, Canes Venatici, Coma Berenices, Draco, Leo, Leo Minor, Lynx
Ursa Major location
Ursa Major is visible at latitudes between 90°N and 30°S. It covers 1,280 square degrees or 3.10% of the night sky, being the third-largest constellation. Observers in the Northern Hemisphere can see it every night, all year round.
Where is the Big Dipper in the sky?
The Big Dipper (also known as “the Plough” or “the Wagon”) is Ursa Major’s asterism, the prominent pattern of stars that is smaller than the constellation itself. To find it, look for the shape of the bowl with a handle. It’s the most recognizable pattern in the sky, consisting of bright stars that form the tail and the hindquarters of the Great Bear. In the Northern Hemisphere, the Big Dipper is high in the sky during the spring months and close to the horizon during the fall. As the mnemonic goes: “spring up and fall down.” In the Southern Hemisphere, the asterism is best seen from April to June in the regions north of latitude 25°S.
How to find Ursa Major?
The other parts of Ursa Major are more challenging to recognize than its bright dipper. The head and upper torso of the Great Bear include four bright stars on the right side of the Big Dipper. Three more stars form the forelegs. Finally, the rear legs consist of four stars; they extend down the left edge of the bowl.
Discover other sky objects using the Big Dipper
The two stars on the outer edge of the Big Dipper’s bowl — Merak and Dubhe — are called “the Pointers” because they point at Polaris. To find the North Star, draw an imaginary line between these two stars and extend it about five times. When you find Polaris, you are on your way to finding the Little Dipper and, eventually, the Ursa Minor constellation. Polaris is the brightest star in Ursa Minor that marks the end of the Little Dipper’s handle.
Moreover, you can locate Arcturus with the help of the Big Dipper. To find it, extend the arc of the Big Dipper’s handle to about 30°, preserving its natural curve. Arcturus is the orange star, the brightest one in the Boötes constellation. It’s best seen during the spring and summer months in the Northern Hemisphere and during the winter and autumn in the Southern Hemisphere. If you prolong the curve further, you can also locate Spica, the brightest star in the Virgo constellation.
Draw an imaginary line between two Big Dipper’s stars at the handle end of the bowl — Megrez and Phad — and extend it about 45°. You’ll find Regulus, the brightest star in the Leo constellation.
How to find Ursa Major with stargazing apps?
If you aren’t sure you located Ursa Major or the bordering constellations correctly, check it with stargazing apps.
To find the Great Bear with the help of Star Walk 2 app, tap on the magnifier icon and start typing “Ursa” in the search bar. The first result, Ursa Major with the bear icon, is the one you need. Tap on it, and the arrow will guide you to the constellation in the night sky based on your geolocation.
The other helpful stargazing app Sky Tonight works similarly. To find the Great Bear, tap on the magnifier icon and type “Ursa” in the search field. Tap on the first result — Ursa Major — then tap on the target icon to see its current position in the sky. If you tap on the compass icon, the arrow will help you find the constellation based on your geolocation. In Sky Tonight, you can also find the Big Dipper asterism on its own. To do that, type “Big Dipper” in the search field and choose the relevant result.
Learn about the 7 free stargazing apps and find the best one for you.
Ursa Major brightest stars
The most known Ursa Major stars are the ones that form the Big Dipper: Benetnash (Alkaid), Mizar-Alcor, Alioth, Megrez, Dubhe, Merak, and Phad (Phecda). Mizar-Alcor is a system that contains at least three pairs of stars, but it looks like a single star to the naked eye. The brightest stars in the asterism are Alioth, Dubhe, and Merak.
Alioth (ε UMa, HIP 62956, HR 4905)
Alioth (Epsilon Ursae Majoris) is the brightest star in the Great Bear and the 31st brightest in the night sky, shining at a magnitude of 1.8. It is located in the Big Dipper’s handle, closest to the bowl. The star is almost 3 times more massive than our Sun, located more than 82 light-years away from it. It’s also one of the 58 primary stars historically used in celestial navigation. “Alioth” originates from the Arabic “alyat al-hamal,” which means “the sheep’s fat tail.”
Dubhe (α UMa, HIP 54061, HR 4301)
Dubhe (Alpha Ursae Majoris) is the second brightest star in Ursa Major, the upper right point of the Big Dipper’s bowl. Its apparent magnitude is 1.8. Dubhe is the spectroscopic binary system where the primary star Dubhe A is an orange giant of around 4.25 solar masses. Along with Alioth, Dubhe is included in the list of the primary navigational stars. The star’s name originates from the Arabic phrase meaning “the back of the Greater Bear.” Dubhe is one of the two Big Dipper’s stars that help to find Polaris.
Merak (β UMa, HIP 53910, HR 4295)
Merak (Beta Ursae Majoris) is the fifth brightest star in Ursa Major, the bottom right point of the Big Dipper’s bowl. Along with Dubhe, it serves as “a pointer” to find Polaris. Merak is a bluish-white subgiant star with an apparent magnitude of 2.3. It contains 2.7 solar masses and is located at around 80 light-years from our Sun. The name “Merak” comes from the Arabic “al-maraqq,” meaning “the loins.”
Deep-sky objects in Ursa Major
Ursa Major contains 514 deep-sky objects, though most of them are very dim. Seven of the Ursa Major deep-sky objects are listed in the Messier catalog. These are:
- Messier 40 (M40, Winnecke 4),
- Messier 81 (M81, NGC 3031, Bode’s Galaxy),
- Messier 82 (M82, NGC 3034, Cigar Galaxy),
- Messier 97 (M97, NGC 3587, Owl Nebula),
- Messier 101 (M101, NGC 5457, Pinwheel Galaxy),
- Messier 108 (M108, NGC 3556),
- Messier 109 (M109, NGC 3992).
Let’s take a closer look at the three best-seen objects.
Messier 81 (M81, NGC 3031, Bode’s Galaxy)
M81 is a spiral galaxy shining at a magnitude of 6.9. Its approximate location is about 12 million light-years from our Solar System. You can spot the galaxy’s faint light even through binoculars, but its core is seen only through a telescope. The best time to observe Bode’s Galaxy is in April.
Messier 97 (M97, NGC 3587, Owl Nebula)
The Owl Nebula is one of the four planetary nebulae in the Messier catalog. It has a magnitude of 9.9. and can be seen as a faint dot through a pair of binoculars, good weather given. You’ll get a better view of the nebula with more professional optics — its two owly eyes can be seen through 10-inch and larger telescopes.
Messier 82 (M82, NGC 3034, Cigar Galaxy)
M82 lies at a distance of 12 million light-years from the Earth. It is known for its extraordinarily high rate of star formation — stars there are being born 10 times faster than in our Milky Way. The Cigar Galaxy shines at a magnitude of 8.41. It is best observed in April through a professional telescope. Still, you can spot it as a patch of light even with binoculars.
Ursa Major mythology
The name Ursa Major means “the great bear” in Latin. The first mention of the constellation in writing belongs to Homer. In “The Odyssey,” he refers to it as “the Bear, which men also call the Wain”.
Ursa Major Greek myths
As the Greek myth explains, there was a nymph Callisto who took a vow of virginity to Artemis. Zeus, however, loved her, and they had a son Arcas. One version says Artemis tried to kill Callisto because she broke her vow, but Zeus transformed his lover into a bear in the sky. In another version, it was Hera who tried to kill Callisto out of jealousy. The third version explains further that the son Arcas grew up while his mother wandered as a bear for fifteen years in the mountains. Once Arcas met Callisto on the hunt and nearly killed his mother, but Zeus interrupted and turned Callisto into Ursa Major and Arcas into the Boötes constellation.
Ursa Major Native American myths
Native Americans have two general Ursa Major myths. According to the first one, the constellation represents seven brothers and their sister who fled to the sky to escape a pursuer. The brothers became the seven major stars of the Big Dipper, and the girl became the small star Alcor. In the gruesome story, the children were chased by their mother’s head, which their father had decapitated.
Another widespread myth tells about the bear chased by a hunter or hunters. As the Iroquois tribes’ legend goes, six hunters had chased a bear. Three of them were killed by a stone giant, and the other three were transferred to the sky together with the bear to become Ursa Major.
The Great Bear in other cultures
The Great Bear constellation shares similar origin stories across North America and South Asia. It might mean that the constellation got its name over 50,000 years ago when a Paleolithic bear cult existed. Ursa Major has other ancient names too:
- Mesopotamian: Mul Mar Gid Da (“the constellation of the long chariot”);
- Egyptian: Khepesh (“the thigh”);
- Chinese: Bei Dou (“the northern bushel”);
- Hindu: Saptarshi (“the seven sages”);
- Persian: Haptoiringa (“the seven thrones”).
Why is Ursa Major so important?
Ursa Major is the most recognizable constellation. It appears in the culture of various nations, from Homer and the Bible to Native American myths. It is also a great reference point to search for other stars and constellations. Find out how much you know about constellations in our challenging quiz.
How many galaxies are in Ursa Major?
Ursa Major contains 511 galaxies in total, but only a few are well-seen. The best targets for amateur telescopes are the Cigar Galaxy (M82, NGC 3034) and Bode’s Galaxy (M81, NGC 3031). Read on to find more deep-sky objects that are easy to observe.
Is the North Star part of Ursa Major?
The North Star (also known as Polaris) is located in the constellation Ursa Minor. The stars Merak and Dubhe of the Ursa Major constellation help to find Polaris in the night sky — you need to draw an imaginary line between them and then extend it five times. To quickly locate any star or constellation, check the stargazing video tutorial.
Is the Big Dipper the same as Ursa Major?
The Big Dipper is Ursa Major’s asterism — the prominent pattern of stars that is smaller than the constellation itself. It forms the hindquarters of the Great Bear. The Big Dipper consists of seven main stars, six of which are the brightest in the whole constellation. The rest of Ursa Major is hard to see with the naked eye when the sky is light-polluted. Learn how to find Ursa Major and other constellations in our infographic.
Why are the constellations Ursa Major and Ursa Minor called circumpolar constellations?
Ursa Major and Ursa Minor constantly rotate around Polaris and never set below the horizon in the Northern Hemisphere. That’s why they are called circumpolar constellations. They can be above or below the North Star, depending on the season. The most known circumpolar constellation in the Southern Hemisphere is the Southern Cross. Check your knowledge of the constellations in the guessing game!
Now you know there is more to Ursa Major than just the famous bowl-shaped asterism. It is significant for culture, science, and even marine navigation. Moreover, it helps to locate other stars and constellations in the night sky. So, start exploring the universe from the Big Dipper!
Text Credit: Vito Technology, Inc.