About the Object

The Horsehead (near the center of the frame) and the Flame Nebulae (left of center). The Horsehead, also known as Barnard 33, is a dark silhouette in front of the bright emission nebula IC 434. It was first recorded on a photographic plate taken by Williamina Fleming in 1888 at Harvard College Observatory. Edward Pickering, the director of the observatory at the time, credited Williamina with the discovery, though John Louis Dreyer, who was updating the general catalog of nebulae and star clusters at the time, was not so "generous" and removed Fleming as the discoverer and replaced her name with Pickering's. The omission was eventually corrected, but not till about twenty years later.The Flame Nebula is a similar combination of bright emission nebula and obscuring foreground dust and gas creating a complex structure that appears to resemble a campfire in space. At the center of the Flame Nebula lies a cluster of newly formed stars many of which still show circumstellar disks, donut shaped accretions of material that may eventually become planetary systems. The cluster is only seen in infra-red images which can penetrate the obscuring dust.The Horsehead and Flame along with all of the surrounding hydrogen gas visible within this image are part of the much larger Orion Molecular Cloud complex. The gas in this image is glowing because it is fluorescing under powerful ultraviolet light from several stars within the image. The gas around the Horsehead is likely glowing because of Sigma Orion's (the bright multiple star above and a little to the right of the Horsehead), while the source of UV radiation for the Flame nebula is thought to be Alnitak, the bright star just above the Flame.

About the Image

This wide field image is three degrees per side, meaning there is enough room to fit six full moons across the image--it's a big swath of sky. Because the field of view is so wide, the image was made as a 3 x 2 panel mosaic with each panel binned 2x2 to reduce the processing time.  Each panel consists of 35 separate subexposures of five minutes each, so the total integration time across all six panels is eighteen hours. Processing included cosmetic correction, registration, normalization, image weighting, integration, Drizzle, photometric mosaic, cropping, denoise, star reduction, stretching, and local contrast enhancement using a combination of HDRMT and MMT.