M13, the Hercules Cluster, is about 25,000 light-years away and contains several hundred thousand stars. It is low in the northeast at nightfall, along the line that connects the top two stars in the Keystone, a lopsided square that outlines the strongman's torso.
Weekly Stargazing Tips
Provided by StarDate.org. Unless otherwise specified, viewing times are local time regardless of time zone, and are good for the entire Lower 48 states (and, generally, for Alaska and Hawaii).
May 7: Hercules Cluster
May 8: Saturn and Aquarius
Aquarius the water bearer is in the east-southeast before dawn. The planet Saturn is near the left edge of the constellation. The solar system's second-largest planet looks like a bright star.
May 9: Moon and Elnath
The star Elnath represents the point of one of the horns of Taurus, the bull. It appears near the crescent Moon the next couple of nights, quite low in the early evening sky. It is above the Moon tonight, and to the lower right of the Moon tomorrow night.
May 10: Leo Triplet
Leo is best known for its bright stars, especially Regulus, its brilliant heart. But the lion also contains quite a few bright galaxies. Leading the list are three galaxies that form the Leo Triplet: M65, M66, and NGC 3628.
May 11: Crowning the Crown
Corona Borealis, the northern crown, stands half-way up the eastern sky as darkness falls this evening. It is a small semicircle of moderately bright stars that opens to the left. It is crowned by a binary star system known as Alphecca.
May 12: Moon and Twins
The Moon passes especially close to the star Pollux tonight - the brighter "twin" of Gemini. The star stands just to the right of the Moon at nightfall. The other twin, Castor, is farther along the same line.
May 13: Head Cases
The star Rasalhague represents the head of Ophiuchus the serpent bearer, while Rasalgethi is the head of Hercules. Rasalhague climbs into good view in the east by 10 p.m., with fainter Rasalgethi above it by about the width of three fingers held at arm's length.