✨ M6 (Butterfly Cluster)
Object data
| Type | Open cluster |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h40m05.9s (265.0245°) |
| Declination | -32°13'00" (-32.2167°) |
| Magnitude | mag 4.2 |
| Apparent size | 25′ |
| Other designations | NGC 6405 |
An open cluster in Scorpius, also called the Butterfly Cluster for its pattern of stars resembling a butterfly with open wings.
Midnight transit date (best season to observe and image)
Location: Tokyo (change)
Around Jun 12, 2026
The date it transits around midnight (transit altitude about 22°)
This date has already passed this year. Next year (2027) it will be around Jun 13.
For about 2–3 weeks either side of this date, the object stays high from evening to dawn — its observing season.
Best time to observe tonight
Tonight (Oct 11 evening – Oct 12 dawn) · Location: Tokyo (full darkness = end of astronomical dusk to start of dawn, altitude ≥ 15°)
Moon tonight: New moon (age 29.2 days, 0% illuminated) — Little moonlight — a good time for faint objects
It does not reach 15° during full darkness tonight (it is high only in daytime or twilight at this time of year).
Night (sunset – sunrise)
Full darkness (dusk – dawn)
Moon up (darker = brighter moon)
Best time to observe (thick line)
Now
Sunset 17:11 → Dusk 18:36 → Dawn 4:19 → Sunrise 5:44