Ursa Major: The Great Bear Beyond the Big Dipper

Ursa Major is the Great Bear, a constellation that most people only half-recognize: they spot the seven-star pattern inside it, the Big Dipper, and stop looking. The full bear is far bigger than that famous shape.

Ursa Major covers 1,280 square degrees of sky, making it the third-largest of the 88 constellations recognized by the International Astronomical Union. It sits in the northern sky. Some of its stars can be seen from southern latitudes too, but the farther south you are, the lower the pattern appears and the less of it rises.

Check the night sky guide to see whether it's up from where you are tonight.

Ursa Major at a glance

• Type: A full constellation, one of the IAU's 88 — not to be confused with the Big Dipper, the asterism (a recognizable star pattern that isn't an official constellation) inside it.
• Where: Northern sky, bordering Draco, Boötes and six other constellations.
• Size: 1,280 square degrees — third-largest constellation in the sky.
• Visible from: Northern latitudes and parts of the Southern Hemisphere; how much rises, and whether the familiar Dipper ever sets, depend on latitude.
• Best seen: Spring evenings, when the Big Dipper climbs high; it culminates, or reaches its highest point, in April.
• Brightest star: Alioth, magnitude 1.76, in the Dipper's handle.

The Big Dipper inside the Bear

Seven stars carry the whole reputation: Alkaid, Mizar, Alioth, Megrez, Dubhe, Merak and Phecda. Together they form the Big Dipper, also called the Plough or the Wagon — an asterism, not one of the 88 official constellations, but the tail and hindquarters of the larger bear. You can browse it alongside other landmark patterns in the constellation guide.

Two of those stars do the real work for beginners. Merak and Dubhe sit on the outer edge of the Dipper’s bowl. Draw a line from Merak through Dubhe, then continue it about five times the distance between them to reach Polaris, the North Star, in Ursa Minor. That's why they're called the Pointer Stars.

The handle offers a second trick. Follow its curve outward about 30° and you reach Arcturus, the orange star in Boötes; keep following the same arc and it leads to Spica in Virgo. A separate line, drawn from Megrez through Phecda and extended about 45°, points to Regulus in Leo.

Six of the seven Dipper stars sit near second magnitude, bright enough to survive most light pollution unless they're low on the horizon. Megrez, the star linking bowl to handle, is noticeably fainter at third magnitude and can vanish in haze or a bright sky.

Mizar and Alcor: a double that's really six

Mizar sits right at the bend in the handle, with the fainter star Alcor close beside it. Under a dark sky many people can split the pair with the naked eye; in binoculars it's easy.

The pair turns out to be far more crowded than it looks. Spectroscopic analysis shows Mizar A, Mizar B and Alcor each have their own tight companion, so that single point of light is at least six stars.

Mizar and Alcor are both part of the same stellar association, roughly 1.5 trillion miles apart, though it isn't confirmed whether they're actually bound to each other by gravity.

Beyond the Dipper: stars and neighbors

Alioth, the brightest star in the whole constellation, is a chemically peculiar blue-white subgiant nearly three times the Sun's mass, about 82 light-years away. It ranks as the 31st-brightest star in the night sky and was historically one of the stars navigators used to fix a position at sea.

Dubhe, the second-brightest, marks the bowl's upper corner and is one of the two Pointer Stars. It's a spectroscopic binary whose primary is an orange giant about 4.25 times the Sun's mass.

Alkaid, at the tip of the handle, is a hot blue-white main-sequence star around six solar masses — and unlike most of its neighbors, it doesn't share their common motion through space, so it only appears to belong to the same moving family from our vantage point.

Ursa Major borders eight other constellations, but two are easy to pick out once you know the Dipper. Draco curls around nearby Ursa Minor, and Boötes announces itself with Arcturus, the bright orange star at the end of the handle's arc. Explore either one further in the bright stars guide.

Deep-sky objects in the bear

The constellation holds seven objects in the Messier catalog, though one, M40, is only an optical double star rather than a true deep-sky object — that leaves six genuine targets.

M81, known as Bode's Galaxy, is a spiral galaxy at magnitude 6.9, about 12 million light-years away. Binoculars can catch its faint glow under dark skies; a telescope makes the brighter central region and surrounding haze easier to distinguish.

M82, the Cigar Galaxy, sits at roughly the same distance and shines at magnitude 8.41; it's forming stars about ten times faster than the Milky Way's central region does, a pace visible in images even if not in the eyepiece.

M97, the Owl Nebula, is a planetary nebula — the glowing shell a dying star sheds — at magnitude 9.9, one of only four planetary nebulae in the entire Messier catalog.

Astronomer William Parsons named it in 1848 after two dark patches that looked like a pair of eyes; seeing those eyes is much harder than detecting the nebula itself and depends on aperture, sky darkness and observing experience.

How to see it

Spring evenings give the best view in the Northern Hemisphere, with the Big Dipper riding high and easy to trace against a darker sky. By autumn it drops much lower and gets harder to pick out, especially from lower northern latitudes.

From the Southern Hemisphere, the Dipper is visible low on the northern horizon from roughly April to June, and only from about 25°S northward.

At sufficiently northern latitudes, the Big Dipper stays above the horizon as it wheels around Polaris. Farther south, parts of it set; the full official constellation covers more sky than the seven-star pattern. The live sky map can show exactly where it sits from your location right now.

A short route works well for a first look:

1. Find the bowl and handle of the Big Dipper — six stars near second magnitude do most of the work.
2. Draw from Merak through Dubhe, then continue about five times their separation to reach Polaris.
3. Follow the handle's curve outward to Arcturus, then on to Spica.
4. Draw a line from Megrez through Phecda and extend it to Regulus in Leo.

Moonlight washes out the fainter galaxies fast, so it's worth checking the Moon guide before planning a night around M81 or M82. A darker site, found through the light-pollution map, makes the difference between a blank patch of sky and a genuine smudge of galaxy light in binoculars.

The Owl Nebula's eyes, the Cigar Galaxy's burst of star formation, the tangle of six stars hiding inside Mizar — each reward a longer look than the Dipper alone invites. The bear keeps more of itself in reserve than most people ever bother to find.