🌌 M99 (St. Catherine's Wheel)
Object data
| Type | Galaxy |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 12h18m49.7s (184.7070°) |
| Declination | +14°24'59" (+14.4164°) |
| Magnitude | mag 9.9 |
| Apparent size | 5.4′ × 4.7′ |
| Other designations | NGC 4254 |
A face-on spiral galaxy in Coma Berenices with beautiful arms, sometimes called St. Catherine's Wheel.
Midnight transit date (best season to observe and image)
Location: Tokyo (change)
Around Mar 23, 2026
The date it transits around midnight (transit altitude about 69°)
This date has already passed this year. Next year (2027) it will be around Mar 23.
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