Constellations · 2 of 5

The Winter Hexagon

Which six bright stars make the grandest shape in the winter sky?

Six first-magnitude stars from six constellations form the grandest pattern in the winter sky.

You’ll be able to trace the Winter Hexagon’s six bright stars round from Rigel to Capella.

12 steps · about 9 min

Before this: Orion: The Hunter (6 min)

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Working out when this is best placed from where you are…

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Kept for this guide only, until you change it here — your map settings, and every other guide, stay as they are.

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Sources

HYG stellar database v4.2 — star positions, magnitudes and every separation quoted here
Gaia DR3 (ESA, 2022) — parallaxes for Procyon, Pollux, Castor, Capella and Aldebaran
van Leeuwen, A&A 474, 653 (2007) — Hipparcos re-reduction, Sirius at 2.64 pc
Bond et al., ApJ 840, 70 (2017) — HST astrometry of Sirius B, mass 1.02 M☉
Hexagon area computed by spherical excess from the six HYG positions: 1,940 deg²

← GUIDES

The ring is the Winter Hexagon: six of the 21 brightest stars in the sky, from six constellations, with a seventh, Betelgeuse, inside it. It holds a tenth of the sky above your horizon. Now build it, corner by corner.

Begin at Rigel, Orion's blue-white foot: the Hexagon's south-western corner. The measured line is the first side, running south-east to Sirius.

Sirius, the brightest star in the night sky, is simply close. Its companion is a white dwarf, a Sun's mass in an Earth-sized body. Now find the next corner yourself: Procyon, north-east.

Procyon, nearly as close, has a white dwarf too. North of it stand two twins, Castor and Pollux, and only one of them is a corner of the Hexagon. Which? Guess on the card.

Pollux, the brighter twin and the nearer to the last corner, is the one. The twins are nothing alike: Pollux one orange giant with a planet, Castor six stars bound together. Now the longest side, north-west to Capella.

Capella passes almost overhead from 40°N. It looks like one yellow star and is two yellow giants orbiting every 104 days, too close for any ordinary telescope to split. The next side runs south to Aldebaran.

Aldebaran, the orange eye of the Bull, is 44 times the Sun's width. The measured side runs back to Rigel and closes the ring: six corners, six constellations.

Built. Inside it sit Betelgeuse and the marked anticentre: you face straight away from the galaxy's core, out through the thin edge of its disc — why the Milky Way is faint behind so many bright winter stars.

Turn the Hexagon sideways: each corner slides out to its distance. Sirius and Procyon stop close by; Rigel runs on a hundred times farther. Sirius is bright because it's close; Rigel because it's enormous.

Now sort them: colour across, blue left to red right; up, every star at one distance. Sirius and Procyon sit on the main band, ordinary stars; Pollux, Capella and Aldebaran are giants, up and right; Rigel towers over all.

Six hours of a winter night: the Hexagon climbs, rides highest in the south and tips toward the west. Tonight, find Orion's foot, Rigel, and go round the ring from there, six corners with Betelgeuse inside.

The ring once more, with Betelgeuse inside. On a clear night, trace its six corners.

Six corners, Rigel round to Aldebaran
Sirius is bright because it is close
Rigel is bright because it is huge

The Winter Hexagon

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