03-09-2016, 10:19 AM
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Introduction :
Adaptive optics is a new technology which in effect removes this atmospheric tremor and helps the astronomers see the images through earth based telescopes more brightly
==> Without using this system, the images obtained through telescopes on earth are seen to be blurred, which is caused by the turbulent mixing of air at different temperatures
==> It brings together the latest in computers, material science, electronic detectors, and digital control in a system that warps and bends a mirror in a telescope to counteract, in real time the atmospheric distortion
What Is Adaptive Optics ?
Adaptive optics refers to optical systems which adapt to compensate for optical effects introduced by the medium between the object and its image ==> In order to avoid atmospheric aberration, one can turn to larger telescopes on the ground, which have been equipped with ADAPTIVE OPTICS system.==> With this setup, the image quality that can be recovered is close to that the telescope would deliver if it were in space. ==> Images obtained from the adaptive optics system on the 6.5 m diameter telescope, called the MMT telescope illustrate the impact
Basic Principle:
==> An adaptive optics system reflattens the wave fronts by reflecting the light of a deformable mirror whose shape is changed in real time to introduce an equal but opposite distortion ==> The information on how to distort the mirror comes from a wave front sensor, an instrument that measures optical aberration imposed by the atmosphere on light from a star.==> After the light reflects of the deformable mirror, a beam splitter sends part of the light to a camera that will capture the high resolution image produced by the adaptive optics
Seeing Infrared :
In the infrared, the hardware of adaptive optics consists of an existing telescope, complete with its primary and secondary mirrors, and adds a separate box of optics, including the deformable mirror, to perform the atmospheric compensation
==> One is that each additional optical surface beam train absorbs some of the light from the target object in the sky, making the object appear fainter.
==> Also it emits light by virtue of its warmth, introducing thermal noise, further degrading the astronomers, ability to detect faint objects