Reflection nebula
M78 (M78)
In Orion (Ori) • Magnitude 8.0 • 8.0 arcminutes
Open the free AstroPlanner with M78 pre-selected, scored against your telescope, location, and the live cloud forecast.
The brightest reflection nebula in the sky — it glows not by emitting its own light but by reflecting starlight off interstellar dust, giving it a distinctive blue-white sheen. Part of the same vast Orion Molecular Cloud as M42, the Hubble Space Telescope has detected hundreds of newly forming stars hidden within it.
M78 at a glance
| Catalog IDs | M78, N 2068 |
| Type | Reflection nebula |
| Constellation | Orion (Ori) |
| Right ascension | 05h 46m 41s |
| Declination | +00° 04' 12" |
| Apparent magnitude | 8.00 |
| Surface brightness | 13.0 mag/arcsec² |
| Angular size | 8.0 × 6.0 arcmin |
| Max altitude at 45°N | 45° |
| Best imaging months | Sep, Oct, Nov |
How to image M78
M78 sits in the constellation Orion at right ascension 05h 46m 41s and declination +00° 04' 12". 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.