How Do I Determine Which Constellation a Star Is In?

Find a sky map or stargazing guidebook that matches your location and season. These can be purchased as books or printed free from several websites.

Step outside. Allow your eyes to adjust to the darkness. Orient your sky map. Sky maps are set to the horizon, so the center of the map should be the top of the sky above you. Look at the largest dots on the map and match them to the brightest stars in the sky, turning the sky map until it matches the view above you. You can also identify which direction is north and align your map accordingly. Use a very dim flashlight or red light to read the chart because it makes it easier for your eyes to readjust to the darkness after you turn the flashlight off.

Pick out stars in the sky and identify them by their names on your sky chart. Learn their positions in relation to stars and constellations you already know, such as the Big Dipper, so you can identify them later. Identify some of the main constellations, such as Orion, Cassiopeia and Ursa Major and note their relation to one another.

Don't identify stars in relation to the moon or planets. Because planets and the moon appear to move through the sky from night to night, they can't offer points of reference. A main difference between stars and planets is that stars appear to twinkle, while planets glow steadily. Many planets, if observed through binoculars or a telescope, are shaped like disks instead of round.

Use the stars and constellations you know to identify those you don't know. If you see an unfamiliar star in the sky, use familiar constellations to gain reference. Consult your sky map and identify the new star and its constellation.