Image Credit & Copyright: Don Goldman, Astrodon Imaging (http://www.astrodonimaging.com)
The Dark Tower is an elongated dark cloud of dust and gas of about 40 light-years across, located some 5,000 light-years away from Earth in the southern constellation of Scorpius.
Silhouetted against a crowded star field, the Dark Tower is known as a cometary globule – an isolated, relatively small cloud of gas and dust within the Milky Way – which is extending from the lower right to the top of the tower, left and above center of the image. Probably, clumps of dust and molecular gas are collapsing to form stars within this dark nebula.
Its swept-back shape is sculpted by the intense ultraviolet radiation from very hot stars in NGC 6231, which lies about 100 light-years away from the Dark Tower (off the upper edge of the image). The direction of the radiation source can be seen from the flow pattern in the dark cloud.
NGC 6231, also known as the False Comet Cluster or the Northern Jewel Box, is an open cluster of about 3.2 million years old, which is approaching us at 22 kilometers per second. The cluster belongs to the young Scorpius OB1 association, a loosely organized group of hot, massive OB-type stars.
The energetic ultraviolet light from the stars in NGC 6231 is also causing the red glow (from hydrogen gas) of the extensive bright rims (emission nebulae) around the top of the Dark Tower and the background medium, such as the interesting “bridge to nowhere”, extending from the tip of the Dark Tower toward the left side of the image. There are several bluish reflection nebula embedded within the Dark Tower. These structures are stellar nurseries.
This image is taken on 08.04.2010 using the Riverland Dingo Observatory in Moorook, S. Australia. A synthetic luminance was created from the unbinned RGB data. H-a data were added to the synthetic luminance and to the red and blue color channels.