AAO image reference AAT 36a. « Previous || Next »
Top is W, left is N. Image width is about 48 arc min
Image and text © 1999-2010, Australian Astronomical Observatory, photograph by David Malin.
This curious dark nebula is one of the best-known images in astronomy, probably because of its chance likeness to a recognisable form. The horse-head shape is an extension of a large cloud of dust which fills the lower part (east) of the picture and hides the light of stars beyond. The outer surface of the dusty gas (IC 434) runs roughly north-south and is illuminated by sigma Orionis (off the top of the picture) which causes the hydrogen there to fluoresce, outlining the horse-head shape. The diffuse haze to the left of the image (north) is scattered light from the bright star zeta Orionis. Though conspicuous here, the Horsehead is very difficult to see visually, even with a large telescope. A bright star is partially enveloped in the dust cloud and its scattered light is seen as the large, irregular blue reflection nebula, NGC 2023. All these objects are about 1350 light years distant in the constellation of Orion.
AAT 36. The Horsehead Nebula and NGC 2023 (landscape format, wide field)
AAT 36b. The Horsehead Nebula
UKS 1. The Horsehead Nebula and NGC 2024 in Orion
UKS 1a. The Horsehead Nebula and NGC 2024 in Orion
UKS 23. Faint nebulosity near Orion and Horsehead Nebulae
Constellation of Orion (external site)
For details of photographic exposure, search technical table by AAT reference number
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