THE HORSEHEAD NEBULA
- IC434
- Deepsky 1800mm hALRGB
- Constellation Orionis

One of the most beautiful and impressive celestial objects in the winter Milky Way is the famous Horsehead Nebula. Wrapped in the red swath of IC 434, an emission nebula in the constellation Orion at the celestial equator, through which the Horsehead Nebula, a dark cloud on the same line of sight, is backlit and thus becomes visible.
The nebula is located south of the bright star Alnitak in Orion's Belt. Due to its equatorial position, it can be observed from all inhabited areas of the Earth, depending on the time of year. Due to its faint brightness, however, it is only visible with long exposures or with medium-sized telescopes. The nebula borders the molecular cloud Orion B to the west and reaches 70 arcminutes in length but only a few arcminutes in width. Its shape resembles a long, striped blade running in a north-south direction. The eastern part is partially obscured by a dark cloud that belongs to Orion B and is known as the Horsehead Nebula because of its characteristic shape.
The Horsehead Nebula is about 1500 light years away from Earth and appears to be a quarter of the size of the Earth's moon. The nebula is a collection of cold gas and dust that emits very little light in the visible spectrum and therefore appears dark.
Investigations in the millimeter and submillimeter range show that the nebula consists mainly of molecular hydrogen and that it also contains a large number of different simple hydrocarbon compounds, some of which also contain oxygen and sulphur. These molecules have a temperature of around 100 Kelvin in the outer area and 15 Kelvin in the core area of the nebula; it has approximately 27 times the mass of the sun. The gas masses are moving, which is why the nebula will lose its resemblance to a horse's head in a few thousand years.



Equipment & imaging data:
Dream Aerospace Systems 16-inch astrograph imaging telescope called Astronomical Telescope for Educational Outreach (ATEO-1) with 1800mm focal length. Camera FLI16803, Chroma filter set.
Lights: L 14x 300s Bin1x1 // R 16x 300s, G 11x 300s & B 10x 300s Bin 2x2 (flats, darks, bias calibrated, dithering)
Location: USA, Utah, Great Basin Desert. Remote Telescope Insight Observatory. Acquired image dataset.

6" 150PDS Skywatcher
Lights: hA 14x 600s Bin1x1 (flats, darks, bias calibrated, dithering). Camera Atik16200 Mono, filter set Astronomik
Location: Tulln a.d. Donau, Austria. Balcony observatory.

Image processing:
Mainly Pixinsight, Photoshop, Lightroom, GraXpert, BTX Blur Terminator, Noise Terminator, Star X Terminator