The Dark Tower is a large cometary globule (GN 16.43.7.01) which is situated around 5000 light years away in the constellation of Scorpius.
The term cometary globule comes from the shape of the dense dust region which appears to have a head and tail.
The object contains a small blue reflection nebula as well as dark nebula components.
Imaged in LRGB and H alpha on my Planewave CDK 700 at Observatorio El Sauce, Chile.
Image acquisition and processing: Mike Selby