M39
open cluster · Cygnus · 4.6ᵐ
A large, loose triangle of about thirty stars northeast of Deneb. Best at the lowest magnification you have.
Notable facts
About the same apparent size as the full Moon.
In brief
Which constellation is M39 in?
M39 lies in Cygnus.
Is M39 visible to the naked eye?
4.6ᵐ — visible to the naked eye (under dark skies).
When is the best time to observe M39?
Best observed in August.
Data
- RA / Dec (J2000)
- 21h 32m · +48° 26′
- Type
- open cluster
- Constellation
- Cygnus
- How to observe
- 4.6ᵐ — visible to the naked eye (under dark skies)
- Angular size
- 32′
- Designation
- M39 · NGC 7092
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° | 78° · never sets | — |
| +55° | 83° · never sets | — |
| +45° | 87° · never sets | — |
| +30° | 72° | 30° |
| 0° | 42° | 42° |
| −35° | 7° | 24° |
Geometric altitude at upper culmination, atmospheric refraction not included. Positive latitudes are in the northern hemisphere.
Culmination time by month
| Month | Culmination |
|---|---|
| January | 13:47 |
| February | 11:39 |
| March | 09:54 |
| April | 08:01 |
| May | 06:06 |
| June | 04:00 |
| July | 01:56 |
| August | 23:55 |
| September | 22:02 |
| October | 20:14 |
| November | 18:13 |
| December | 16:04 |
Upper culmination in local solar time — no time-zone or daylight-saving correction applied.