Obituary: David Allen

David Allen, astronomer: born Altrincham, Cheshire 30 July 1946; married 1969 Carol Andrews (one son, two daughters); died Sydney, New South Wales 26 July 1994.

DAVID ALLEN, the astronomer, lay fatally ill in Sydney last week while earth-sized cyclones from Comet Shoemaker-Levy raged over the planet Jupiter, photographed by Allen's camera attached to the Anglo-Australian Telescope (AAT) in rural New South Wales.

The first and only permanent member of the scientific staff of the AAT, Allen made a unique contribution to astronomy in Britain and Australia: he realised that with the latest technology he would be able to see amazing things in the Universe even through the sometimes murky infra-red windows in the atmosphere over the AAT.

Allen learnt the early laborious techniques at Cambridge and in Minnesota and California, assembling simple infra-red pictures of planets and nebulae point by point. Then arrays of detectors were invented, at first primitive with coarse grain, later with the clarity of high-resolution television. Allen garnered arrays from his contacts, young engineers in the silicon valleys, eager to give him their hand-made chips, knowing he would use them to see something interesting. He installed the arrays into subtle astronomical equipment to see infrared from black holes and planets.

Why infra-red? Infra-red comes from warm solids in space, like the dusty cocoons where planets are born. It also penetrates cloud. Allen used his camera, in what he described as possibly his most significant piece of work, to see, for the first time, through Venus's otherwise opaque clouds down to its solid mountainous surface.

David Allen's energy showed in an impressive corpus of scientific papers, a wide range of enthusiasms, and his galloping walk, favouring his stiff leg, his blond forelock of hair flicking over his brow. He wrote innumerable articles and books about astronomy, some with his wife Carol. Patrick Moore, who first knew Allen as a short-trousered nine-year-old who had come to look through his telescope, particularly admired Allen's writing skill. He was a frequent guest on The Sky at Night, Moore gathering in television cameramen at the weekend to take advantage of a rare visit by him to Britain. It was on such a visit last year that Allen realised that his sight had suddenly deteriorated. A brain tumour was diagnosed. It was an 'unusually aggressive cancer', he wrote in an electronic mail message circulated globally to friends. 'What else would you expect from David Allen?'

Allen warned his scientific collaborators not to expect him to contribute further to joint studies with his camera. His intellect remained, and he discoursed to a bedside gathering of the AAT's governing board what the telescope's future should be.

Because of his leg, Allen did not drive; it was Carol who peered over the huge steering-wheel of a Land-rover as they explored outback Australia, sunhatted children aboard. He seemed happiest exploring unknown places, the Nullabor Plain or Venus, in the company of his family and his friends.

(Photograph omitted)