M 23 Deep sky · Open cluster in Sagittarius · M 23 · NGC 6494
M 23
A broad, rich open cluster in the Sagittarius Milky Way, scattered with chains and arcs of stars.
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- Type
- Open cluster
- Designations
- M 23 · NGC 6494
- Constellation
- Sagittarius
- Apparent magnitude
- 5.5
- Apparent size
- 25′
- Position (J2000)
- RA 17h 57m · Dec −18° 59′
It is about as wide as the full Moon, which is about 31′ across. The Sun passes 4° from it around late December, and for about 28 days of the year it sits within 15° of the Sun, lost in its glare.
When to see it
On the night of Fri 18 Jun 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | 20:54 | 01:11 · 20° | 05:27 |
| New York EDT | 20:15 | 01:05 · 30° | 05:56 |
| Singapore GMT+8 | 19:19 | 01:16 · 70° | 07:13 |
| Sydney GMT+10 | 17:15 | 00:07 · 75° | 06:59 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 21° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 74° up in the north.
- When is the best time of year to see it?
- Around mid June, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid September it is highest in the early evening, and in mid March not until the hours before dawn.
- 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
It lies north-west of the Teapot, on the border with Ophiuchus. Binoculars show a hazy patch; a telescope, dozens of stars.
Look for
From 50° north it climbs to 21°; from 35° north it climbs to 36°; from the equator it climbs to 71°; from 35° south it climbs to 74°.
Look for
Magnitude 5.5 against the faintest star each can show: the eye under a city sky, 4.5 (1.0 short); the eye under a dark country sky, 7.0 (1.5 to spare); 50 mm binoculars under that dark sky, 11.0 (5.5 to spare); a 100 mm telescope there, 12.5 (7.0 to spare). Through 7×50 binoculars, whose field is about 7.1° across, it spans 6% of the field’s width; through a 100 mm telescope at 50×, a field about 1° across, it spans 42% of the field’s width.
Words used here
Its constellation
Nearby in Sagittarius
- Nebula Lagoon Nebula
- Nebula Trifid Nebula
- Globular cluster Great Sagittarius Cluster
- Nebula Omega Nebula
- Open cluster Black Swan Cluster
- Open cluster Webb's Cross
- Open cluster Small Sagittarius Star Cloud
- Open cluster M 25
- Globular cluster M 28
- Globular cluster M 54
- Globular cluster Specter Cluster
- Globular cluster M 69
- Globular cluster M 70
- Globular cluster M 75