05/31/2021 – Ephemeris – Hercules the constellation

This is Bob Moler with Ephemeris for Memorial Day, Monday, May 31st. Today the Sun will be up for 15 hours and 19 minutes, setting at 9:20, and it will rise tomorrow at 6:00. The Moon, 2 days before last quarter, will rise at 2:23 tomorrow morning.

Orion, the hard luck mythological Greek hunter gets a splashy constellation in the winter sky, but the greatest hero of all, Hercules, gets a dim group of stars on the border between the spring and summer stars. At 11 p.m. Hercules is fairly high in the east. It is located above and a bit right of the bright star, Vega east-northeast. Hercules’ central feature is a keystone shaped box of stars, called the Keystone laying on its side, which represents the old boy’s shorts. From each left corner stars extend lines of stars that are his legs, from the right stars, the rest of his torso and arms extend. So in one final indignity he’s upside down in our sky. For those with a telescope, Hercules contains the beautiful globular star cluster Messier 13.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Hercules can be found in the east among the line of constellations at around 11 pm in late May or early June between the bright stars Arcturus and Vega. Created using Stellarium and GIMP.

M 13 is found on the western side of the Keystone. In this orientation when Hercules is in the east, it is the top side. Created using Stellarium with an annotation.

M 13, the Great Globular Star Cluster in Hercules. Credit: Scott Anttila.

M 13 is the brightest and finest globular star cluster in the northern hemisphere of the sky. It’s at a distance of 25 thousand light years. Some amateur astronomers can spot M 13 with the naked eye. It is a fuzzy spot in binoculars. I can barely resolve some of its stars in an 8-inch (200 mm) telescope. It’s a wonderful sight in anything bigger! The slightly dimmer M 92 is also slightly farther away at nearly 27 thousand light years. 

Click on any of the images above to enlarge them.