A brightening Moon limits deep-sky options, but this cluster never fails to disappoint: M13, the great globular in Hercules the Strongman.
- Messier 13 (M13), a globular cluster in Hercules, is favorably positioned for observation around 10 PM local daylight time, reaching a height of approximately 70° in the west.
- M13 possesses a magnitude of 5.8, rendering it observable with binoculars or telescopes; naked-eye observation is possible under dark skies, though optics are recommended for the specified time.
- Locatable using Vega and Arcturus as reference points, or Zeta and Eta Herculis, M13 features an apparent size of roughly 20 arcminutes and contains hundreds of thousands of stars.
- Provided local time data includes sunrise (6:02 AM), sunset (8:10 PM), moonrise (5:09 PM), moonset (1:03 AM), and a moon phase of 79% waxing gibbous (based on 40° N 90° W).
The northern sky’s standout globular, M13 in Hercules, is placed just right to give it a try tonight. Around 10 P.M. local daylight time, M13 is some 70° high in the west and won’t fully set until an hour before sunrise. Glowing at magnitude 5.8, it will show up well in binoculars or any telescope. You can find it about ⅓ of the way along a line drawn from Vega in Lyra to Arcturus in Boötes. Once you’ve located the Keystone of Hercules, you can home in on the cluster’s location by looking ⅔ of the way along a line from magnitude 3.0 Zeta (ζ) to magnitude 3.5 Eta (η) Herculis. Although visible as a dim smudge of light to the naked eye on a dark night, tonight you will need your optics to find it.
This great globular spans roughly 20’ and houses several hundred thousand stars, making it an incredibly old, dense ball of stars to be marveled at. Take your time, slowly bumping up the magnification to see more and ever-fainter stars appear at the edges of its dense core.
Sunrise: 6:02 A.M.
Sunset: 8:10 P.M.
Moonrise: 5:09 P.M.
Moonset: 1:03 A.M.
Moon Phase: Waxing gibbous (79%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
For a look ahead at more upcoming sky events, check out our full Sky This Week column.
