Reflection nebula
Blue Horsehead Nebula (IC4592)
In Scorpius (Sco) • Magnitude 3.6 • 1.0 degrees
Open the free AstroPlanner with Blue Horsehead Nebula pre-selected, scored against your telescope, location, and the live cloud forecast.
Faint reflection nebula in Scorpius lit by Nu Scorpii.
Blue Horsehead Nebula at a glance
| Catalog IDs | I 4592 |
| Type | Reflection nebula |
| Constellation | Scorpius (Sco) |
| Right ascension | 16h 11m 59s |
| Declination | -19° 27' 17" |
| Apparent magnitude | 3.60 |
| Surface brightness | 20.7 mag/arcsec² |
| Angular size | 60.0 × 40.0 arcmin |
| Max altitude at 45°N | 26° |
| Best imaging months | May, Jun, Jul |
How to image Blue Horsehead Nebula
Blue Horsehead Nebula sits in the constellation Scorpius at right ascension 16h 11m 59s and declination -19° 27' 17". To frame and integrate it well, AstroPlanner will compute the optimal moonless window for tonight from your location, the field-of-view fit against your sensor and focal length, the suggested total integration time given your aperture and sky Bortle class, and a cloud-aware schedule that drops it from the plan if your nearest cloud forecast spike overlaps the best altitude window.