Word: flickering
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...telescope in space so that the instrument would be free from temperature changes and the pull of gravity, both of which can subtly distort the shape of earthbound mirrors. They also wanted it to rise above earth's turbulent atmosphere, whose constant roiling makes the stars appear to flicker. But scientists have learned to make mirrors that can change their shapes, enabling ground-based telescopes to overcome the problems of gravity and temperature fluctuations. Soon it may be possible to compensate for the atmosphere's turbulence as well...
Active-optics mirrors can refocus in seconds, but the atmosphere's turbulence can make a star seem to flicker hundreds of times a second. Compensating for the flicker calls for a still experimental system called adaptive optics. Different versions of the equipment are being developed at the University of Hawaii and Johns Hopkins University, as well as in Europe...
...reference star within the telescope's field of view and looks for the shimmering caused by currents in the atmosphere. When the sensor detects disturbances, it sends signals to electrodes flanking the plastic mirror. The electrodes create electric fields that make the plastic bulge or dip, canceling out the flicker. Both the Hawaii and Johns Hopkins teams expect to test their mirrors early in 1991. If they work, the adaptive-optics systems could be used on virtually any existing telescope...
Sununu, like Bush, grew up in the shadow of a highly successful father in a comfortable home in a leafy bedroom community, attended private boarding school and displayed nary a flicker of rebellion. The crucial difference is that Bush was heir to both material and social comfort, while Sununu was always an outsider...
Midmorning. "It has been a quiet revolution," the woman is saying. She is sixtyish, an actress in the Berliner Ensemble, the repertory theater founded by Bertolt Brecht. In the corner of the room, images flicker on the television screen. The pictures are of villas and hunting dachas and the commentator is talking about hundreds of millions of deutsche marks smuggled out of the country and into Swiss bank accounts...