SkyRef / Star patterns

The Big Dipper

An asterism in Ursa Major, formed from 9 stars. Not one of the 88 constellations.

The pattern

Stars in the figure9
Brightestmagnitude 1.77
Sits inUrsa Major
Right ascension12.3h
Declination+56°
Also calledthe Plough

What to look for

The most useful pattern in the northern sky, because it points at everything else. Follow the two stars at the end of the bowl and you land on Polaris; follow the curve of the handle and you arc to Arcturus, then speed on to Spica.

The Big Dipper is centred near right ascension 12.3 hours, declination +56°. It sits well north on the sky and is comfortably placed for northern hemisphere observers.

Asterism, not constellation

The International Astronomical Union recognises 88 constellations, and they divide the whole sky between them like countries on a map. The Big Dipper is not one of them — it is a pattern picked out of Ursa Major. That makes it an asterism: a shape people recognise and name, with no official standing whatsoever.

The distinction matters less than it sounds. Asterisms are usually easier to find than the constellations containing them, which is exactly why they survive.

Find it tonight

SkyRef can draw the Big Dipper in its real position for wherever you are — switch on the asterism layer and it appears dashed across the constellations it runs through.

Open the live sky map →

Other star patterns

the Big Dipperthe Little DipperOrion's Beltthe Summer Trianglethe Winter Hexagonthe Great Square of Pegasusthe Teapotthe Sicklethe Northern Crossthe Wthe Keystonethe False Crossthe Southern Pointers