Hercules

The late spring and early summer months are the best time to observe the constellation named after Hercules, the mythological Roman hero famed for his strength and courage while subduing monsters, bandits, and criminals. The constellation is one of 48 listed by the second-century astronomer Ptolemy. Now, Hercules is the fifth-largest of the 88 constellations recognized by today’s astronomers and the largest of the 50 constellations containing no stars brighter than apparent magnitude +2.5.

To locate this ancient but rather dim constellation, look almost straight up soon after the sun has set to find Arcturus - a red giant star situated only 36.7 light-years away from Earth and the fourth brightest star in the heavens - by arcing to it from the handle of the Big Dipper. Next, draw a straight line to Vega, the fifth brightest star in the sky, in the Lyra constellation. Roughly two-thirds of the way from Arcturus to Vega, your line will pass through Hercules’ torso, a four-star asterism named the Keystone of Hercules. At this time of night, Hercules’ will appear upside down, with his running legs above his torso and his club below.

Meanwhile, Hercules is home to many double-star systems and a triple-star system observable with a small amateur telescope. The constellation also lodges two globular clusters, M13 and M92.

M13, containing more than 300,000 stars some 25,000 light-years away from us, is the brightest globular cluster in the northern hemisphere and, while faint, may be found by the unaided eye on very clear nights.

M92 is the oldest known globular cluster, at 14 billion years of age. It is visible in binoculars as a fuzzy star. However, a medium-aperture amateur telescope will reveal individual stars within M13.