Horsehead Nebula

Designations: Horsehead Nebula (Barnard33)
Object Type: Dark Nebula
Constellation: Orion
RA: 05h 41m 0.0s
Dec: -02 deg 23m 59s (Epoch 2000)

Visual Magnitude: unknown
Size: About 5 arcmin
Distance: unknown
Discoverer: unknown

Visual Description: The Horsehead Nebula (Barnard33) is one of the most photographed but least observed objects in the sky. It is incredibly challenging for visual observers, and until rather recently it was a prize worth crowing about even among photographers. The blob of darkness lies halfway along the streamer of faint nebulosity that runs for 1 degree south from Zeta Orionis, the easternmost belt star. The streamer IC434 (the abbreviation IC stands for Index Catalogue, and suplement to the New General Catalogue of Nebulae and Clusters of Stars by J.L.E.Dreyer), is a bit brighter than the Veil Nebula in Cygnus, and no great feat to see. But recognizing the dark blotch B33 is another matter. The Horsehead was first photographed about 1900, but was believed to be only a void in IC 434. Barnard appears to have been the first person to suggest that it was actually an obscuring cloud of material seen in silhouette. Deep-sky observers diagreed on its visibility in amature telescopes. The Horsehead is harder to see by far than the nebula around R Monocerotis (Hubble's Variable Nebula). It is much harder than the veil in Cygnus or spiral galaxy M33 in Triangulum. Possibly it is more difficult than the Merope Nebula in the Pleiades. In any case, the observer should wait for special weather and use a photograph as a detiled finder chart. Scattered light from 2nd-magnitude Zeta foils may attempts to find the Horsehead, since the two are separated by only 1/2 degree. Another reason that many searches fail is that observers are looking for the wrong-sized objsect. When seen in telescopes between 10 and 16 inches in aperture, it always appears very tiny. Knowing just where to look is half the battle. The Horsehead is only about 5 arc minutes across. Amateurs accustomed to seeing it on large-scale photographs mad with professional telescopes end up looking for an object that is much too big.

Telescope: Stellarvue SV80s APO Refractor
Focal Length: 384mm (480mm X 0.8 reducer)
Mount: Takahashi NJP 160
Camera: SBIG ST-10XME
Exposure: 18 10-Minute Exposures through a Hydrogen Alpha filter
Other: SBIG ST-402ME autoguider

Image Processing: CCDStack and Photoshop CS2

The visual descriptions for the Horsehead Nebula was written by Walter Scott Houston in the book "Deep-Sky Wonders" by Walter Scott Houston with selections and comentary by Stephen James O'Meara Page 6. ISBN number 0-933346-93-X.

Astro Images

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