This article by Gareth Huw Davies was first published in The Sunday Times, October 13th, 1996.

The camera that can see in starlight.

A video camera that operates in starlight, the Lo-Lite, has been developed by a British company. Tonight (Sunday, Oct 13th) BBC 2 screens its first film. Mara Nights penetrates the almost total blackout of a moonless Serengeti night to show familiar African wildlife as it has never been seen before.

The Lo-Lite, which contains an image intensifier originally designed as a tank driving sight and a silicon chip developed for high-definition TV, pushes video camera technology close to its limit. By amplifying tiny amounts of available light, the camera is about as sensitive as the night sight of the animals it is filming.

For many years the night was a secret kingdom for wildlife film-makers. They first broke down the nocturnal barrier by habituating their animal subjects to low levels of artificial light over a number of sessions. By lighting their subjects at a low angle from the back or side, they kept the shot partly dark to maintain the illusion of night.

The other method was to "illuminate" the scene with infrared light, invisible to human and animal eyes, and film with cameras sensitive to the infrared wavelength. Most night sequences in wildlife and other documentaries are now shot this way. However when the BBC commissioned natural history cameraman Martin Dohrn to film animals at dead of night in the Masai Mara in Kenya, he decided to dispense with artificial light altogether. "Film is a suspension of disbelief. With night filming it is even more so, because you are adding light, even if it is infrared. So you are expecting people to believe it is dark when there is an obvious light source."

TV viewers have long been familiar with the capabilities of video cameras to film in low light, particularly at sporting fixtures in the gathering gloom. However the best available video camera used in night wildlife filming was still unable to operate at anything less than the light of a full moon. Dohrn and TV engineer Arnold Bellis toured manufacturers and chose high specification components - a key piece was an image intensifier until recently restricted to military use, a telescope-like tube double the diameter and twice as sharp as those normally used in video cameras.

Ammonite, Dohrn's Bristol-based company, built two identical cameras. "The technology is not fundamentally new. But we have maximised its potential. These items have never before been put together in this combination" Photons, tiny particles of light, pass through a special wide-aperture lens and strike a sensitive, charged surface at one end of the image intensifier. This surface absorbs the photon's energy and releases more energy in the form of an electron which is focused down the intensifier tube. At the end of the tube is a phosphor screen, much like the screen in a TV's cathode ray tube. The energy the electrons release when they strike the phosphor causes it to glow, creating a picture. Because the intensifier tube is shaped like an inverted telescope, it demagnifies the image, making it much brighter.

The intensifier is bonded directly onto a silicon chip, chosen for its sensitivity to match the output of the phosphor - it is four times more receptive than chips normally used. This chip then translates the image into a broadcastable video picture. The cameras revealed animal behaviour which few naturalists had ever seen before. "Lions and hyenas behave quite differently in total darkness," said Dohrn. "For example, lions abandon normal hunting techniques and rely on bumping into things then jumping on them."