Constellations and Stargazing

Orion the Hunter features three bright stars — Alnitak, Alnilam, and Mintaka — forming the unmistakable belt. It is one of the most recognized constellations in the winter sky.

Sirius, also called the Dog Star, shines brighter than any other star visible from Earth. It belongs to the constellation Canis Major and is especially brilliant on winter nights.

Polaris, the North Star, sits within one degree of the celestial north pole, so it appears nearly motionless in the sky while other stars rotate around it. Sailors and travelers have used it for navigation for thousands of years.

The Big Dipper is an asterism — a recognizable star pattern — that forms the back and tail of Ursa Major, the Great Bear. Its two outer bowl stars point directly toward Polaris.

Cassiopeia, named for a vain queen in Greek mythology, forms a clear W or M shape depending on the season. Because it circles the North Pole, it never sets for observers in most of North America and Europe.

The International Astronomical Union officially recognizes 88 constellations that together cover the entire celestial sphere. The original 48 were catalogued by the ancient Greek astronomer Ptolemy.

The 12 zodiac constellations mark the ecliptic — the apparent yearly path of the Sun across the sky. Astrology borrowed these same constellations to create the familiar star signs.

Vega is the brightest star in the small constellation Lyra the Harp and is the second-brightest star visible from the Northern Hemisphere. It forms one corner of the well-known Summer Triangle.

Betelgeuse is a red supergiant star and one of the largest stars visible to the naked eye — it is so enormous that if placed at the center of our solar system, it would extend past the orbit of Mars.

Deneb, Vega, and Altair form the Summer Triangle, a large asterism high overhead on summer evenings. Deneb belongs to Cygnus the Swan and is actually one of the most luminous stars in our galaxy.

Crux, the Southern Cross, is the smallest of all 88 constellations but one of the most famous. Mariners south of the equator use it to find true south, just as Northern Hemisphere sailors use Polaris.

Spica is the brightest star in Virgo the Virgin and one of the fifteen brightest stars in the entire night sky. A helpful way to find it is to follow the arc of the Big Dipper's handle to Arcturus, then continue to Spica.

The Pleiades star cluster has been recognized and named by cultures around the world for thousands of years. On a clear dark night you can see six or seven stars with the naked eye, though the cluster actually contains hundreds.

Andromeda was chained to a rock as a sacrifice to the sea monster Cetus before Perseus saved her. Both Andromeda and Perseus are neighboring constellations in the northern sky, and the Andromeda Galaxy — visible to the naked eye — lies within the constellation.

Claudius Ptolemy recorded his list of 48 constellations in his work the Almagest, which became the foundation of Western astronomy for over a thousand years. All 48 of his original constellations are still part of today's official list of 88.