Horsehead Nebula
What is Horsehead Nebula?
Nebulae· Distance 1,375 ly. A cold dust cloud just below Alnitak at the eastern end of Orion's Belt, silhouetted as a horse's head against a glowing red backdrop. Famous in photographs, yet one of the hardest nebulae to see by eye.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Horsehead Nebula is in your sky right now: https://nowsky.org/solar/sky?sel=horsehead — location and time set automatically, no login.
Distance and scale
| Distance | ~1,375 ly |
|---|---|
| Size | ~3.5 ly tall |
| Type | dark nebula |
| Constellation | Orion |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- How far is Horsehead Nebula from Earth?
- ~1,375 ly.
- What kind of object is Horsehead Nebula?
- dark nebula.
- In one line, what is Horsehead Nebula?
- Nebulae — A cold dust cloud just below Alnitak at the eastern end of Orion's Belt, silhouetted as a horse's head against a glowing red backdrop.
- Where is Horsehead Nebula in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
The mane as Webb saw it — a front being eaten by light
In 2024 Webb imaged the top of the Horsehead — the horse's mane — at the highest resolution yet. The picture shows the nebula's edge frayed into threads as it is worn away by starlight from behind. That edge is a photodissociation region, where ultraviolet light from hot stars meets the cold molecular cloud and breaks its molecules apart, and the Horsehead, the nearest such site, has become the specimen for measuring that physics at full scale.
At the rate it is being eroded the Horsehead will disperse within about five million years. Its present shape is an accident of dense dust holding out for a while against the light behind it, and we happen to live in the short span while the accident lasts. The thin threads at the tip of the mane in Webb's image are about the width of the solar system, and none of them has yet gathered enough to become a star.
The nebula in depth
The Horsehead Nebula (Barnard 33) does not shine on its own; it is a dark nebula that blocks light. The red emission nebula IC 434 behind it acts as a backlight, and in front a cold pillar of dust about 3.5 light-years tall stands out as the black profile of a horse's head. Williamina Fleming of Harvard Observatory first spotted it on a photographic plate in 1888.
The cloud belongs to the Orion molecular cloud complex, packed so densely with molecular hydrogen and dust that starlight cannot pass through. Hubble's 2013 infrared image peered through the silhouette to show stars forming inside and the cloud's three-dimensional shape, and in 2023 James Webb caught ultraviolet light eroding the dust along the horse's mane. The structure should dissipate in about five million years.
In the Sky view the position is easy: just south of Alnitak, the easternmost star of Orion's Belt. Seeing it is another matter — the backdrop is so faint that neither eyes nor binoculars will show it, and even a large telescope needs a hydrogen-beta filter to catch the silhouette. Winter evenings, when Orion rides high in the south, are the time to try.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.