Friday, May 8, 2009

Horse Head Nebula - New vision

The Horse-Head Nebula

This photograph capturing light 1500 years old was taken by pioneering photographer and astronomer David Malin (Image: David Malin)

Every astronomy buff is familiar with the Horsehead nebula in the constellation Orion - a dark, dense molecular cloud in the shape of an equine head and neck, silhouetted against the fiery light of ionised hydrogen gas. The optical effect is completed by the less often appreciated "mane" behind the horse's head (pictured left).

The mane is a cloud of cold gas, mostly hydrogen, that is fluorescing. Since this fluorescence is red, David Malin used a red filter to take this photograph. He then applied "unsharp masking" which, belying its name, increases image sharpness by bringing forth features that are otherwise too faint to see. The 1500-year-old light from the nebula was collected using the Anglo-Australian Telescope in New South Wales, Australia.

Malin's innovative techniques and extraordinarily long exposure times - some as long as an hour - have created images of galaxies and nebulae that reveal their hidden details, and have furthered our understanding of the universe. He has helped identify two new types of galaxies - shell and proto-galaxies - among the faintest objects ever detected by a ground-based telescope.

A more familiar representation of the Horsehead Nebula

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