M23
open cluster · Sagittarius · 5.5ᵐ
A rich open cluster — some 150 stars against one of the densest Milky Way fields. At its best in a wide field of view.
Notable facts
About the same apparent size as the full Moon.
In brief
Which constellation is M23 in?
M23 lies in Sagittarius.
Is M23 visible to the naked eye?
5.5ᵐ — visible to the naked eye (under dark skies).
When is the best time to observe M23?
Best observed in June.
Data
- RA / Dec (J2000)
- 17h 57m · −19° 01′
- Type
- open cluster
- Constellation
- Sagittarius
- How to observe
- 5.5ᵐ — visible to the naked eye (under dark skies)
- Angular size
- 27′
- Designation
- M23 · NGC 6494
Observing tip
Best in binoculars or a telescope at low power, so the whole cluster fits in the field of view.
Altitude above the horizon by latitude
| Latitude | Maximum altitude | Rise azimuth |
|---|---|---|
| +60° | 11° | 131° |
| +55° | 16° | 125° |
| +45° | 26° | 117° |
| +30° | 41° | 112° |
| 0° | 71° | 109° |
| −35° | 74° | 113° |
Geometric altitude at upper culmination, atmospheric refraction not included. Positive latitudes are in the northern hemisphere.
Culmination time by month
| Month | Culmination |
|---|---|
| January | 10:11 |
| February | 08:04 |
| March | 06:19 |
| April | 04:25 |
| May | 02:31 |
| June | 00:25 |
| July | 22:21 |
| August | 20:20 |
| September | 18:27 |
| October | 16:38 |
| November | 14:37 |
| December | 12:29 |
Upper culmination in local solar time — no time-zone or daylight-saving correction applied.