National Geographic : 1955 Aug
Sky Survey Plates Unlock Secrets of the Stars Seven years in the making, the 1,758-plate atlas charts three-fourths of the heavens-all that can be photographed with good quality from Palo mar Mountain-to a depth of 600 million light years. Stars appear black against a white sky, for astronomers usually study negatives direct from the camera. Here George O. Abell scans Andromeda Galaxy, a spiral system similar to our Milky Way, whirling 9 quintillion miles from the earth. Opposite page shows Andro meda in the exact size used by the Sky Atlas. The standards we set for the Survey were high, so high that for a time they seemed im possible to fulfill. That was why so many plates were rejected and why it took us seven years instead of four, as planned. Once Dr. Gerard P. Kuiper, a distinguished astronomer of the Yerkes and McDonald Ob servatories, was visiting at Palomar and ad miring some of the Sky Survey plates. "These are superb," Dr. Kuiper said. "I have seldom seen such definition." "They are good," replied Dr. Rudolph Min kowski, who directed the Survey project. "But they are not good enough. We are making them again." Dr. Kuiper shook his head in disbelief; but the new plates were much superior. The astronomers who operated the Big Schmidt and produced the Survey plates Dr. Albert G. Wilson, now director of the Lowell Observatory, Messrs. Robert G. Har rington, George O. Abell, and others-found 6 Milton IIyman the work exciting and rewarding as new celes tial objects came into their ken. But it was sometimes cold, lonely, and heartbreaking.* Once Mr. Abell was observing on such a night as astronomers pray for; the light from countless stars pierced down through a beau tifully clear and steady Palomar sky. The "seeing," as we say, was excellent. Afterward Mr. Abell took his photographic plates to our darkroom and started to develop them. That is quite a ticklish job, and no body enters the room while Survey plates are being developed. "Presently," he recalls, "somebody flung open the door." It was Charles E. Kearns, able night assistant for the Big Schmidt. "Get back! Close the door! Have you gone mad?" Abell shouted. "Relax," Kearns said. "It really doesn't * See "Our Universe Unfolds New Wonders," by Albert G. Wilson, NATIONAL GEOGRAPHIC MAGAZINE, February, 1952.