M 92 Deep sky · Globular cluster in Hercules · M 92 · NGC 6341
M 92
The other globular cluster in Hercules, outshone by its neighbour M 13 but every bit as fine, and among the oldest in the galaxy.
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- Type
- Globular cluster
- Designations
- M 92 · NGC 6341
- Constellation
- Hercules
- Apparent magnitude
- 6.4
- Apparent size
- 14′
- Position (J2000)
- RA 17h 17m · Dec +43° 08′
The full Moon, about 31′ across, is 2.2 times as wide. The Sun comes no nearer to it than 66°, around early December, so it is never lost in the Sun’s glare, which reaches about 15° out.
When to see it
On the night of Tue 8 Jun 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | Never sets | 01:09 · 82° | — |
| New York EDT | 15:31 | 01:04 · 88° | 10:37 |
| Singapore GMT+8 | 19:11 | 01:15 · 48° | 07:19 |
| Sydney GMT+10 | 20:42 | 00:06 · 13° | 03:29 |
Common questions
- Can I see it from 50° north?
- Yes, on any clear night of the year — it is circumpolar from there and never quite sets, though at its lowest it skims the horizon, where trees and haze will hide it.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 12° up in the north.
- When is the best time of year to see it?
- Around early June, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early September it is highest in the early evening, and in early March not until the hours before dawn.
- How bright is it?
- Magnitude 6.4 in total, but that light is spread over 14′ of sky: on average 20.8 magnitudes per square arcsecond. Against a dark country sky that average stands out; a city’s glow drowns all but its brightest parts.
- Naked eye, binoculars or telescope?
- The naked eye, from a dark country sky, which shows stars to about magnitude 7.0; from a city, binoculars.
Look for
Find the Keystone, then look to its north. Binoculars show a fuzzy star; a telescope, a bright ball.
Look for
From 50° north it is circumpolar and never sets; from 35° north it climbs to 82°; from the equator it climbs to 47°; from 35° south it climbs to 12°.
Look for
Magnitude 6.4 against the faintest star each can show: the eye under a city sky, 4.5 (1.9 short); the eye under a dark country sky, 7.0 (0.6 to spare); 50 mm binoculars under that dark sky, 11.0 (4.6 to spare); a 100 mm telescope there, 12.5 (6.1 to spare). Those limits are for a point of light; its light is spread over its whole size, so it needs some of that margin in hand. Through 7×50 binoculars, whose field is about 7.1° across, it spans 3% of the field’s width; through a 100 mm telescope at 50×, a field about 1° across, it spans 23% of the field’s width.