🌑 LDN 1637
Object data
| Type | Dark nebula |
|---|---|
| Constellation | Monoceros |
| Right ascension | 6h43m38.3s (100.9095°) |
| Declination | +3°56'56" (+3.9489°) |
| Magnitude | (no magnitude data) |
| Apparent size | 66.47′ |
| Other designations | LDN 1637 |
A Lynds dark nebula in Monoceros. Opacity class 2 (1 = faintest to 6 = darkest).
Midnight transit date (best season to observe and image)
Location: Tokyo (change)
Around Dec 28, 2026
The date it transits around midnight (transit altitude about 58°)
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 16 evening – Oct 17 dawn) · Location: Tokyo (full darkness = end of astronomical dusk to start of dawn, altitude ≥ 15°)
Moon tonight: Waxing crescent (age 4.7 days, 23% illuminated)
Oct 16 23:46 – Oct 17 4:23
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.
Night (sunset – sunrise)
Full darkness (dusk – dawn)
Moon up (darker = brighter moon)
Best time to observe (thick line)
Now
Sunset 17:05 → Dusk 18:29 → Dawn 4:23 → Sunrise 5:48