north circumpolar constellations pt.2

Summer

Summer is a season of mixed blessings for astronomers. The nights are warm but short and often hazy. As if that weren't bad enough, we have to contend with swarms of blood-sucking mosquitoes! Haze and insects aside, the summer sky is a veritable gallery of cosmic masterpieces. The Milky Way arches high across the sky, which is richer than its winter counterpart because we now look toward the heart of our galaxy. Dominating the evening sky are three 1st-magnitude stars forming the Summer Triangle. Vega is the brightest of the three and is located in a nifty little constellation called Lyra the Lyre.

The summer sky

1 a.m. on June 1; 11 p.m. on July 1; 9 p.m. on August 1. Add one hour for daylight-saving time.

Astronomy: Roen Kelly

Our second Summer Triangle star, Deneb, is the tail of Cygnus the Swan. Deneb and four other bright stars of the Swan form an asterism called the Northern Cross, which is immersed in the Milky Way. Deneb is at the top of the cross, the star Albireo is at the base. Albireo is a double star famous for its rich colors of golden yellow and sapphire blue. The star pair can be split with binoculars, but the colors can be seen only through a telescope.

Farther south on the Milky Way is the bright star Altair and its parent constellation, Aquila the Eagle. If you follow the Milky Way from Aquila toward the southern horizon, you should find a group of stars that looks like a teapot. This asterism is part of Sagittarius the Archer. This constellation marks the location of our galaxy's center. The area teems with deep-sky treasures — especially bright nebulae and star clusters. To the right of the teapot is the ruddy 1st-magnitude star Antares, the "heart" of Scorpius the Scorpion. Like the winter star Betelgeuse, Antares is a red supergiant star in the last stages of its life. A fishhook-shaped row of stars trailing down and to the left of Antares forms the Scorpion's tail and stinger, while an upright row of three stars to Antares's right marks the location of its claws.

Autumn

As the nights begin to lengthen and a chill pervades the air, the summer Milky Way exits center stage (although the Summer Triangle remains visible in the west until early winter). Following the Summer Triangle is one of the night sky's prettiest constellations — Delphinus the Dolphin. Four stars, arranged like a diamond, form the Dolphin's head, while a fifth creates the tail. You can imagine a dolphin leaping out of the water as you gaze at this constellation.

The autumn sky

1 a.m. on September 1; 11 p.m. on October 1; 9 p.m. on November 1. Add one hour for daylight-saving time.

Astronomy: Roen Kelly

In its wake is a rather barren expanse of sky whose most prominent feature is the Great Square of Pegasus the Winged Horse.

Alpheratz is at the top left corner of the Great Square. From here, two rows of stars branch out and up. This is the constellation Andromeda the Princess. And yes, it is home to the great Andromeda Galaxy. At a distance of 2.7 million light-years from Earth, it's the most remote object readily visible to the naked eye. Through binoculars, however, you'll see an elliptical glow (the galaxy's bright nucleus), which appears larger in small telescopes.