Finding the Summer Triangle

In summer, we need to be able to find the “Summer Triangle”.

The Summer Triangle is a useful reference for finding many summer objects, so you should become very familiar with it.

It consists of the 3 bright stars high overhead and in the south in Summer: Vega, Deneb, and Altair.

The Summer Triangle is not a constellation, but the brightest star in each of 3 separate constellations: Lyra, Cygnus, and Aquila.

Those 3 constellations, and the triangle formed by their 3 brightest stars, are so useful that we will take a moment to look at them more closely and become familiar with them.

Lyra is easy to find because its brightest star, Vega, is the brightest star high in the sky at this time of year. (Only Arcturus is brighter in the summer sky in the Northern hemisphere.)

Most of us don’t know what a Lyre looks like, but the constellation is easy to spot by the distinctive trapezoid (4 stars in a diamond shape) next to brilliant Vega.

Vega is the brightest star in this constellation.

Find Lyra and Vega in this unenhanced sky image. (Click to enlarge.)

The next easiest is Cygnus, the swan.

Deneb, the brightest star in Cygnus, forms his tail. From Deneb you should be able to find the stars that trace the body and at least some of the stars in the outstretched wings.

Practice on this unenhanced sky image. Find Cygnus and Deneb.

Aquila, the Eagle, is the most difficult of the 3 to find.

Ancient observers had darker skies than we do now. The shape of the Eagle’s outstretched wings and extended head is easy to trace once you find the right stars, but, except for Altair, some of the needed stars are quite dim and may be a challenge in light-polluted skies.

Start by finding bright Altair (usually the most southerly and westerly of the 3 bright stars in the triangle), then look for the rest of the eagle. It’s easier if you remember that the eagle is pointing “out ”of the triangle formed by Altair, Vega, and Deneb.

Find Aquila and Altair in this unenhanced sky image.

There you have the “Summer Triangle”, 3 important bright stars,

and 3 important constellations, high in the summer sky.

These stars and constellations will be your guides to many interesting summer objects, so learn to find them quickly and reliably.