Astronauts have been photographing the earth ever since John Glenn made his first orbit on 20 February1962. He looked west, pulled out a camera costing 45 dollars, and took a photograph of the Atlas Mountains in Morocco. All astronauts now take cameras with them, and, because spacecraft fly much closer to the earth's surface than satellites, their photos can pick up remarkably small details - the geometric patterns of farms, ash from volcanoes, light from street lamps - even from 300 miles above. In NASA's climate-controlled vaults in Houston are more than 250,000 such images. On these pages we show just a few of them, selected from a book compiled by Jay Apt, Michael Helfert and Justin Wilkinson

Below: a thousand miles east of Manila, smoke rises from the volcano Pagan along the rim of the Mariana Trench in the Pacific Ocean. Main picture: near the mouth of the Betsiboka River in Madagascar. The brown river water is the result of eroded topsoil after monsoon rains

A 40 square-mile section of the Mato Grosso in Brazil, showing ranches occupying recently-cleared rainforest. The lowlands are occupied only in the dry season

The characteristic shark-tooth pattern of the vast Al Kidan dune field in Saudi Arabia.

Astronauts recognise deserts by their broadly different dune patterns

Rain almost never falls on the Al Kidan dunes. In raking sunlight, the wind-

formed patterns are clearly visible and indicate that winds have shifted over time

Irrigated desert farms in Saudi Arabia. Each green circle is 200 acres of farmland. Saudi Arabia is the only Gulf State to have a surplus of food

A winter view of the farming town of Qostanay in Kazakstan. The walls and rows of closely planted trees prevent topsoil being blown into the sea

The MacDonnell Ranges in Australia's Northern Territory. The 370- million-year-old mountains are the highest point of the continent's arid centre

A cloud wave pattern above South Australia. When wind blows at right angles across a hill or mountain with a flat crest, a series of clouds like ocean waves can form

Snow dusts the highest parts of Black Mesa, a remote ridge of hills

in northern Arizona inhabited by both the Navajo and Hopi Indians

Clockwise from top left: the triangular massif, to the left of the centre of this view, is Mount Everest. Flowing like roads towards the summit, left and right, are the Kangshung and Rongbuk glaciers, which are both in Tibet; Lop Nur is a dry lake on the edge of the Taklimakan desert in China's Xinjiang province; the filament-like track of the Trans- Siberian Railroad stretches left to right through the snow, passing by the city of Omsk and crossing the river Irtysh; snow-covered Onekotan Island, one of the 100-strong Kuril Island chain, which stretches 750 miles off the north-eastern coast of Japan. The circular formation at the top of the picture is the dead form of one of the volcanoes which created this island; also formed by volcanoes are the Galpagos Islands, 600 miles off the South American coast. The centre crater on the larger island is known as Volcano Darwin, named after the man who secured the islands' fame 'Orbit: NASA Astronauts Photograph the Earth' is published in April by the National Geographic Society, pounds 29.95