Astronomically speaking, the beginning of summer brings long days and short nights. Here on Earth, summer tends to bring fantastic weather and clear skies. Though you’ll have to stay up late in order to see them, summer constellations offer a rich number of targets for naked-eye, binocular, or telescopic viewing.
observing targets. Facing south, the Summer Triangle will appear as a large, nearly right triangle defined by the three brightest stars in view. The Summer Triangle contains the alpha stars of three different constellations: Vega in Lyra, Deneb in Cygnus, and Altair in Aquila. This area of the sky is particularly rich since it lies in the plane of the Milky Way. A quick glance through a telescope will uncover dense star fields and gas clouds, such as the Ring Nebula in Lyra. The Summer Triangle also marks the location of the Kepler target stars between Vega and Deneb.
Deneb is the faintest of the trio and is the tail of Cygnus, which is a cross-shaped constellation representing a swan flying roughly to the south. At the head of the swan, nearly halfway between Vega and Altair is a binary star called Alberio. With a telescope, the two stars making up the system can be easily resolved. Albireo is a particularly special binary system because the two stars that make it up are two different colors!
Later in the night, the constellations Pegasus and Andromeda rise in the east. Pegasus contains the “great square” located just east of Cygnus’s wingtip. The constellation Andromeda shares a star with the northernmost corner of the great square. The nearest large galaxy, the Andromeda galaxy is located in this constellation. In especially dark conditions, it can be seen with the naked eye as a fuzzy blob, but in cities and suburbs, it is accessible with binoculars or a small telescope.
Circumpolar constellations are visible throughout the year, but the clear skies of summer can give an observer a great chance to view them as well. Depending on your latitude, the number of circumpolar constellations vary. The closer you are to the poles, the more you will see. However, for the United States and Europe, both the Big and Little Dippers can be seen all night and all year long.
The brighter, Big Dipper can also be used as a guide to find other interesting observing targets. Within the Big Dipper itself, another multiple star system can be seen. With good eyes and a dark sky, the second star in the “handle” of the Big Dipper reveals itself as two stars, called Alcor and Mizar! The system is actually composed of six different stars. Mizar, the brighter, is a quadruple binary system, and Alcor is itself a two-star system. Though a small telescope and binoculars won’t reveal all six stars, they will help you get a better view of the double.
The last two stars of the Big Dipper’s “scoop” point towards the North Star, Polaris, in the Little Dipper. This constellation is fainter, but it is important for navigation. Not only does the star indicate the direction of north, but its elevation from the horizon indicates your latitude. If you travel further north, the Polaris will rise higher and higher in the sky. In the early summer, following the arc of the handle of the Big Dipper allows you to “arc to Arcturus” and find a red giant star in the constellation Bootes. After that, continue to follow the arc and “speed on to Spica,” a blue giant star in Virgo. Other circumpolar constellations visible near the Dippers include Cassiopea, the M or W, and Draco, a faint constellation that snakes its way between the two Dippers and ends near the familiar bright summer star Vega.
As summer comes, take the opportunity provided by clear nights and the end of school to learn some new constellations or telescopic targets. Besides the objects mentioned here, other great telescope and binocular targets are the Messier Objects, a catalogue of galaxies, nebulae, and clusters; or any planets that are visible. Be sure to find a star chart to help you get an accurate picture of what the skies look like at your latitude. Using a red flashlight will help you while working in the dark, but won’t ruin your night vision. Most of all, have fun exploring the night sky!
Printable star charts can be found here: http://www.skymaps.com/downloads.html
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