Great Hercules Cluster
globular cluster · Hercules · 5.9ᵐ
The Great Hercules Cluster — the finest globular in the northern sky, with several hundred thousand stars 25,000 light years away. The 1974 Arecibo message was beamed towards it.
Notable facts
About 1/2 the apparent diameter of the Moon.
In brief
Which constellation is Great Hercules Cluster in?
Great Hercules Cluster lies in Hercules.
Is Great Hercules Cluster visible to the naked eye?
5.9ᵐ — visible to the naked eye (under dark skies).
When is the best time to observe Great Hercules Cluster?
Best observed in May.
Data
- RA / Dec (J2000)
- 16h 42m · +36° 28′
- Type
- globular cluster
- Constellation
- Hercules
- How to observe
- 5.9ᵐ — visible to the naked eye (under dark skies)
- Angular size
- 17′
- Designation
- M13 · NGC 6205 · Great Hercules Cluster
Observing tip
In binoculars it is a fuzzy ball; a 100–150 mm telescope starts to resolve individual stars around the edges.
Altitude above the horizon by latitude
| Latitude | Maximum altitude | Rise azimuth |
|---|---|---|
| +60° | 66° · never sets | — |
| +55° | 71° · never sets | — |
| +45° | 81° | 33° |
| +30° | 84° | 47° |
| 0° | 54° | 54° |
| −35° | 19° | 43° |
Geometric altitude at upper culmination, atmospheric refraction not included. Positive latitudes are in the northern hemisphere.
Culmination time by month
| Month | Culmination |
|---|---|
| January | 08:56 |
| February | 06:49 |
| March | 05:04 |
| April | 03:10 |
| May | 01:16 |
| June | 23:10 |
| July | 21:06 |
| August | 19:05 |
| September | 17:12 |
| October | 15:23 |
| November | 13:22 |
| December | 11:14 |
Upper culmination in local solar time — no time-zone or daylight-saving correction applied.