Aloittaja mistral, 11.12.2010, 22:33:14
LainaaCV-990Modern airborne astronomy began in 1965 when two scientists, Gerard P. Kuiper and Frederic F. Forbes, used Ames' Convair 990 to study the clouds of Venus. The yellowish clouds were believed to contain water, but scientists using ground-based telescopes were unable to conclusively con-firm its presence because water vapor in the Earth's atmosphere obstructed their view."Kuiper realized as you get up to aircraft altitude, you could see out of Earth's atmo-sphere because you get above most of the atmospheric moisture, which blocks most infrared wavelengths," Erickson said. "From the CV-990, Kuiper was able to measure the spectrum of the clouds of Venus in the near infrared and found that they contained essentially no water."That was quite an exciting discovery, because then people really wondered what they were."The answer would elude astronomers awhile longer. While the mobile telescope on the CV-990 was adequate for making the determination that Venus' clouds were very dry, the aircraft, also known as the Galileo I, was constantly needed to support other NASA programs. In addition, a windowless or "open port" telescope, not available on the CV-990, would be required to unravel astronomical mysteries that reveal their se-crets at longer, far-infrared wavelengths.Enter the Ames Learjet.LearjetAcquiring a dedicated airborne observa-tory gave researchers more opportunities and options for studying the heavens. In the late 1960s Frank J. Low of the University of Arizona made far-infrared observations with a novel 12-inch open-port telescope, which he had developed for use in an Ames Learjet."The telescope didn't have a sealed bear-ing," said Erickson. "A narrow spherical gap in the mounting flange allowed it to articulate, with cabin air rushing through the gap. Because of that you couldn't pres-surize the cabin very much, otherwise the gap would close and the telescope would stick. We had to wear oxygen masks all the time."
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