M 43 Deep sky · Nebula in Orion · M 43 · NGC 1982
de Mairan's Nebula
A small comma of glowing gas just north of the Orion Nebula — part of the same cloud, cut off from it by a lane of dust.
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- Type
- Nebula
- Designations
- M 43 · NGC 1982
- Constellation
- Orion
- Apparent magnitude
- 9.0
- Apparent size
- 20′ × 15′
- Position (J2000)
- RA 05h 36m · Dec −05° 16′
The full Moon, about 31′ across, is 1.6 times as wide. The Sun comes no nearer to it than 29°, around mid June, so it is never lost in the Sun’s glare, which reaches about 15° out.
When to see it
On the night of Sat 12 Dec 2026, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 18:38 | 00:10 · 33° | 05:43 |
| New York EST | 18:24 | 00:05 · 44° | 05:46 |
| Singapore GMT+8 | 19:17 | 01:15 · 83° | 07:14 |
| Sydney GMT+11 | 18:53 | 01:06 · 61° | 07:19 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 35° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 60° up in the north.
- When is the best time of year to see it?
- Around mid December, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid March it is highest in the early evening, and in mid September not until the hours before dawn.
- How bright is it?
- Magnitude 9.0 in total, but that light is spread over 20′ × 15′ of sky: on average 23.8 magnitudes per square arcsecond. Against a dark country sky that average stands out; a city’s glow drowns all but its brightest parts.
- Naked eye, binoculars or telescope?
- Binoculars. At magnitude 9.0 it is past the eye, but a 50 mm pair under a dark sky reaches about magnitude 11.0.
Look for
In a telescope it sits beside the Orion Nebula, round, with one star at its centre that lights it up.
History
It is named after Jean-Jacques Dortous de Mairan, who saw it before Messier did and described the star surrounded by its glow.
Look for
From 50° north it climbs to 35°; from 35° north it climbs to 50°; from the equator it climbs to 85°; from 35° south it climbs to 60°.
Look for
Magnitude 9.0 against the faintest star each can show: the eye under a city sky, 4.5 (4.5 short); the eye under a dark country sky, 7.0 (2.0 short); 50 mm binoculars under that dark sky, 11.0 (2.0 to spare); a 100 mm telescope there, 12.5 (3.5 to spare). Those limits are for a point of light; its light is spread over its whole size, so it needs some of that margin in hand. Through 7×50 binoculars, whose field is about 7.1° across, it spans 5% of the field’s width; through a 100 mm telescope at 50×, a field about 1° across, it spans 33% of the field’s width.