Nebula in Orion
M78
The brightest reflection nebula there is, and it makes no light of its own — only dust catching the glare of two hot stars sitting inside it. Blue for the same reason the daytime sky is blue.
It sits in the same great cloud as the Orion Nebula a few degrees south, and its dust is the near face of that cloud catching light rather than a separate object. Several dozen young stars are forming inside it, and this is among the handful of places where an object has been watched brightening and fading as material fell onto a protostar.
- Catalogue
- M78
- Type
- Nebula
- Constellation
- Orion
- Distance
- 1,600 light-years
- Apparent magnitude
- 8.3
- Surface brightness
- 21.1 mag/□″
- Apparent size
- 8′ × 6′
- Right ascension
- 5h 47m
- Declination
- +0.05°
- Found by
- Pierre Méchain, 1780
Small enough that its 8.3 magnitudes arrive concentrated rather than smeared: 21.1 per square arcsecond, which is why it stands out from the sky better than its brightness alone suggests. Why surface brightness is the number that matters.
Could you see it?
Straightforward with 10×50 binoculars from Bortle 4.
| Sky | Eye | 10×50 | 80mm | 130mm | 200mm |
|---|---|---|---|---|---|
| Bortle 1 21.9 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 2 21.7 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 3 21.4 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 4 20.9 mag/□″ | No | Easy | Easy | Easy | Easy |
| Bortle 5 20.3 mag/□″ | No | Challenge | Challenge | Challenge | Challenge |
| Bortle 6 19.3 mag/□″ | No | Challenge | Challenge | Challenge | Challenge |
| Bortle 7 18.6 mag/□″ | No | No | No | No | No |
| Bortle 8 18.1 mag/□″ | No | No | No | No | No |
| Bortle 9 17.8 mag/□″ | No | No | No | No | No |
At the eyepiece
A comet-shaped glow around two stars, and easily the most photographed reflection nebula that people rarely look at directly. No filter helps, because it emits nothing of its own — this is reflected starlight, and filters only take light away.
When, and from where
Highest in the middle of the night in December. Close enough to the celestial equator to rise from almost anywhere on Earth, and to pass overhead for anyone near 0°N.
| Latitude | Highest it gets | |
|---|---|---|
| 60°N Oslo, Anchorage | 30° | |
| 51°N London, Calgary | 39° | |
| 40°N New York, Madrid | 50° | |
| 30°N Cairo, Houston | 60° | |
| 0°N the equator | 90° | |
| 33°S Sydney, Cape Town | 57° |
Nearby in the sky
The whole catalogue →Nothing else in the catalogue is especially close; the nearest is 6.0° apart, which is a separate trip rather than a nudge of the tube. Everything below is measured from M78 itself, not from the middle of Orion.
- M43 De Mairan's Nebula 6.0° apart Orion · magnitude 9.0 · needs more than binoculars
- M42 Orion Nebula 6.2° apart Orion · magnitude 4.0 · binoculars from Bortle 3 or darker
- M50 Open cluster 21° apart Monoceros · magnitude 5.9 · binoculars from Bortle 9 or darker
- M1 Crab Nebula 22° apart Taurus · magnitude 8.4 · binoculars from Bortle 5 or darker
Terms on this page
- Protostar A star that is still assembling itself and has not yet started fusion.
One of 110. Positions J2000; the sky is the final authority.