✨ M13 (Great Hercules Cluster)
Object data
| Type | Globular cluster |
|---|---|
| Constellation | Hercules |
| Right ascension | 16h41m41.3s (250.4220°) |
| Declination | +36°27'36" (+36.4599°) |
| Magnitude | mag 5.8 |
| Apparent size | 20′ |
| Other designations | NGC 6205 |
One of the largest globular clusters in the northern sky, in Hercules. It holds about 300,000 stars and is impressive even in a small telescope.
Midnight transit date (best season to observe and image)
Location: Tokyo (change)
The date it transits around midnight (transit altitude about 89°)
This date has already passed this year. Next year (2027) it will be around May 29.
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 12 evening – Oct 13 dawn) · Location: Tokyo (full darkness = end of astronomical dusk to start of dawn, altitude ≥ 15°)
Moon tonight: Waxing crescent (age 1.1 days, 1% illuminated) — Little moonlight — a good time for faint objects
Hours of full darkness (end of astronomical dusk to start of dawn) when it is above 15° — the darkest sky, mostly clear of buildings and trees.
Sunset 17:10 → Dusk 18:35 → Dawn 4:20 → Sunrise 5:45