Three-colour photograph of the Horsehead Nebula taken by David Malin at the AAO
David Frederick Malin AM (born 28 March 1941) is a British-Australian astronomer and photographer. He is principally known for his spectacular colour images of astronomical objects. A galaxy is named after him, Malin 1, which he discovered in 1986 and which is the largest spiral galaxy so far discovered.
Whilst working at the AAO, Malin developed several photographic processing techniques to maximise the ability to extract faint and low contrast detail from the non-linear response and high densities of photographic plates.
These techniques were initially devised to enhance the scientific return from photography, but Malin is now best known for the series of three-colour wide field images of deep space objects which have been widely published as posters and in books around the world. Most professional astronomical photographs are monochromatic; if colour pictures are required, three images are needed. During his career at the AAO, Malin made about 150 three-colour images of deep sky objects, mostly using plates taken with the 4-metre (160 in) Anglo-Australian Telescope and the 1.2-metre (47 in) UK Schmidt Telescope.
The true-colour images are assembled from three separate monochromatic photographs taken through red, green and bluefilters. Each photographic plate is a special black and whiteemulsion designed for low light conditions and is further enhanced for low light sensitivity by baking in a nitrogen and hydrogen atmosphere. The exposure times are relatively long, varying between 5–60 minutes for each colour, depending on the luminosity of the object. The colour image is re-assembled in the darkroom, where further techniques such as unsharp masking to enhance fine detail might also be applied.
Since the early 1990s, silver-based astrophotography has been largely superseded by digital sensors, but many of the technical advances Malin introduced to the field have been carried over to processing astrophotography on computers.
Malin has published over 250 academic papers on the Astrophysics Data System (ADS)[5] and ten books.[6]
In 2001 he retired from the AAO to concentrate on his own business, David Malin Images, which manages his image collection along with those of related photographers.
