There is probably no single best way to teach an aspiring stargazer how to identify the brightest stars in the night sky. One approach is to consult an astronomy guide that discusses individual constellations in detail. Another way is to obtain sky charts (or even night sky photographs) for different seasons of the year then focus on the constellations with the brightest stars. A third possibility is the hands on approach, which, in my opinion, is the most effective way to learn anything.
Go out on a clear night with a circular sky map, preferably one with a rotating horizon screen that can be aligned with the hour and date of the month. This way, you can automatically tell which constellations and stars are visible from your location on any night of the year. This article will focus on the brightest stars in the night sky visible to observers in the Northern Hemisphere then briefly discuss bright stars visible in the Southern Hemisphere.
The Winter Sky
The highlights of the winter sky include the constellations Taurus (the Bull); Orion (the Hunter); Gemini (the Twins); Canis Major (the Large Dog), and Canis Minor (the Small Dog). As the link above shows, these constellations are located close together in the night sky.
Taurus is shaped like a V and somewhat resembles the horns of a bull. The bulls horns are really the star cluster known as the Hyades. The Bull’s eye is marked by Aldebaran, a bright red star that rises in the early evening by Halloween. Taurus also contains the star cluster called the Pleiades, or Seven Sisters, but these stars are relatively dim.
Southeast of Taurus is Orion, one of the most widely recognized of all constellations. Orion straddles the celestial equator and contains two first magnitude stars: the red supergiant Betelgeuse, which marks Orion’s right arm, and the blue giant Rigel, which marks the Hunter’s left leg. Orion’s belt contains three fairly bright stars called Mintaka, Alnilam, and Alnitak.
Gemini is located northeast of Orion. It contains the bright orange star Pollux and the white star Castor, almost as bright as Pollux but still a second magnitude star. South of Gemini are the constellations Canis Minor, with the bright yellow star Procyon, and Canis Major, which contains Sirius, the brightest star in the entire night sky. An easy way to find Sirius is to trace a line southeast through Orion’s belt until you come to a sparkling white star. Sirius is visible before midnight to Northern Hemisphere observers from November through the following April.
As the winter stars are setting in the west, more bright stars are rising in the east. Three constellations to focus on are Leo (the Lion); Bootes (the Bear Driver); and Virgo (the Virgin).
Leo, located southeast of Gemini, vaguely resembles a lion. It contains the bluish star Regulus, which marks the Lion’s heart. Bootes is shaped like a kite or ice cream cone whose tip is marked by the bright orange star Arcturus. The easiest way to find Arcturus is to draw a line backwards through the handle of the Big Dipper. Southeast of Arcturus is the bright blue star Spica, the only first magnitude star in Virgo. Spica is a little farther from Arcturus than Arcturus is from the Big Dipper. Remember their locations by the mnemonic, “Arc to Arcturus, speed on to Spica.”
The Summer Sky
Three constellations dominate the summer sky: Lyra (the Harp) with the bright blue star Vega; Cygnus (the Swan) with the supergiant star Deneb; and Aquila (the Eagle) with Altair. Vega, Deneb, and Altair form the so called Summer Triangle (actually visible from spring through autumn).
Antares is the other first magnitude star visible in the summer sky. Antares, a red supergiant, marks the heart of Scorpio (the Scorpion), one of the few constellations that look like the object or animal after which they are named. East of Scorpio is Sagitarrius (the Archer) which contains many deep sky objects and marks the center of the Milky Way galaxy.
Two constellations with first magnitude stars rise early in the evening in autumn. These are Auriga (the charioteer) and Piscis Austrinus (the Southern Fish).
Auriga is shaped like a crude shield and contains the bright yellow star Capella. This star is located closer to the north celestial pole than any other first magnitude star. Capella is visible at some time of night nearly all year long from the Northern hemisphere. Piscis Austrinus contains the bright star Fomalhaut. This star rises a short distance above the southern horizon and is visible from September to December for observers in the Northern Hemisphere.
Six bright stars can be seen from latitudes south of the Tropic of Cancer. They are Achernar, marking the end of Eridanus (the River); Canopus, which lies due south of Sirius in the constellation Carina (the Ship’s Keel); Alpha Centauri and Beta Centauri in the constellation Centaurus; and Acrux and Becrux in Crux, better known as the Southern Cross. Southeast of Crux is the Coal Sack, a dark cloud that stands out in sharp contrast to the bright band of the Milky Way.