Educational screen & audio-visual guide (c1956-1971])

Photography Man's "Eye" In Space by William F, Swaiin JLN the hundred years before the present era of rocket astronomy began, the human race had observed the sun's corona for a total span of perhaps one hour. The reason: the corona— the sun's turbulent outer atmosphere— is so drowned by the greater brilliance of the disc that scientists had to wait for the rare and precious moments when the sun was eclipsed by the moon. An astronomer might travel thousands of miles to observe such an echpse, only to have a cloud pass over the sun at a vital moment. Today, however, scientists can peer at the corona at will through the sharp eye of a camera lens caried above the earth's atmosphere by rockets. An orbiting solar observatory was launched by the United States in March. A second, more sophisticed version scheduled for late this year will "see" parts of the corona, extending 20 million miles outward, that never could be observed from earth, even during a total eclipse. Continuous observation of the solar corona is just one of the ways in which scientists have been able to expand our knowledge of the universe since the advent of the space age. Now that we can leave the concealing blanket of the earth's atmosphere behind us, an astronomical revolution is underway. And photography will rank as one of its major tools. At Cape Canaveral, where up to 100 still and movie cameras record every major launching, some $500,000 worth of film is used each year, providing valuable infonnation on everything from the rocket's path to the way the fuel is burning through color analysis of the exhaust. In space, film makes a record of information gathered by the telescope and the spectroscope, two instruments which continue to be the astronomer's most valuable tools. More faithfully than the inattentive and often inaccurate human eye, the camera can turn its superior hght-gathering faculties toward the faintest stars, perceiving color that the unaided eye cannot see. The high-resolution capabilities of modern photographic emulsions could actually record finer images than present-day lenses can transmit. This ultra-sharp vision is particularly important to the rocket astronomer. Among the pictures that have been brought back from outer space: —Never-before-seen white dots floating in sun spots. The dots, less than 200 miles across, are thought to be concentrations of hot gases compressed by the magnetic field of sun spots. Knowing that they exist, scientists can draw advanced theoretical conclusions about the nature of the mysterious sun spots themselves. —Giant swirls of clouds, more than a thousand miles in diameter, with clear eyes in the center. First seen from the weather satellite Tiros I, the huge cloud vortexes dramatically demonstrate the world-wide conditions that affect local weather, and offer a key to how weather is formed. —Spectroscopic breakdowns of ultraviolet hght from the sun which reveal the Lyman-alpha hne: a hydrogen emission line which is impossible to capture from earth because of atmospheric absorption. Such rocket spectrograms furnish valuable information about the composition of the sun's chromosphere, the 10,000 mile deep transition area between the photosphere and the 1,000,000 degree solar corona. Even more spectacular achievements are expected in the near future, from close-up pictures of the surfaces of Mars, Venus and Jupiter, to the discovery of stars never before seen. Because recovery of the film package is not always possible, a large portion of pictures from outer space come to us via the coarser, low-resolution images of television. Even in this kind of system, photography plays a vital role in producing a convenient and permanent record for detailed analysis. Visible light is not the only form of radiant energy utilized by space astronomers. In gathering information about the universe, they explore the entire electromagnetic spectrum, from the longest radio waves to the short emissions below the ultraviolet— including As manager of Eastman Kodak Company's Special Sensitized Products Sales division, WiUiam F. Swann is intimately acquainted ivith photography's role in space research. 370 Educational Screen and Audiovisual Guide — July, 1962