The simplest way to discover the stars is to begin as astronomy itself began, using just your own two eyes. If this evening is clear, why not step outside and spot a few star patterns? The backyard offers convenience, while a local park or schoolyard may provide a view of the horizon less cluttered by buildings or trees.
July’s night sky brings the summer constellations to the fore in the early evening, but these are replaced after midnight by groupings more usually associated with autumn. At dusk, you can hardly miss Vega, Altair, and Deneb, the three bright stars of the Summer Triangle – fully up and dominating the northeast and east.
Boundless topics of interest and targets for observation lie among the Triangle’s constellations of Lyra, Aquila, and Cygnus. There are grand double stars such as Albireo and Epsilon Lyrae, famous variable stars such as Beta Lyrae, Eta Aquilae, and Chi Cygni, and nebulae and supernova remnants including the Ring, the North America, and the Veil.
On July evenings, the Milky Way stretches from the northern horizon in Cassiopeia, through the cross-shaped constellation Cygnus overhead, and down to Sagittarius in the south. Also, notice that the Milky Way splits into two parts in Cygnus because a giant rift caused by interstellar dust blocks starlight from beyond. Both Sagittarius the Archer and its neighbor Scorpius the Scorpion lie in the thickest part of the Milky Way, packed with riches for binoculars or small telescopes. These riches include dozens of star clusters, nebulae, and double stars.
Far to the lower left from bright Antares, the heart of the Scorpion, you will find a close pairing of bright stars sometimes called “the Cat’s Eyes” – Lambda and Upsilon Scorpii. Just to their upper left are the giant open star clusters M6 and M7, both easily visible with the naked eye on a clear, dark night. M6, the Butterfly Cluster, is stunning in small telescopes at low magnification, but M7 is so big and bright that binoculars are all you need to see it well.
In the southwest are the two brightest stars of spring. Arcturus, a red giant at least 110 times more luminous than the Sun, is sinking and Spica is about to vanish below the horizon. Lesser constellations of late spring and early summer also deserve our attention. One of them is fairly conspicuous because it is small and compact: Corona Borealis, the Northern Crown. Only one moderately bright star adorns its semicircular arc: the Alpha Star, named Gemma or Alphekka.
Many other wonders are available in the north. Cepheus, named after King Cepheus in Greek mythology, lies close to the north celestial pole. The constellation resembles a child’s drawing of a house pointing down. Look first beneath the base of the house to find Mu Cephei, one of the most strongly colored stars in the sky. Sir William Herschel called it the Garnet Star because of its deep red tint, which is notable in binoculars or small telescopes.
To help you locate July’s constellations here is a sky map drawn for an observer at 40° north latitude (for example, New York, San Francisco, or Madrid). If you are far south of there, stars above the map’s southern horizon will appear higher than the map shows, and stars in the north will be lower. If you are far north of 40° north latitude, the reverse will be true.