adaptive optics
Since the birth of the telescope 400 years, it has developed from small hand control of optical equipment to large and complex computer-controlled equipment. In the meantime, there are two very important parameters: the telescope's aperture (light-gathering power) and the angular resolution (image sharpness). For an excellent performance of telescopes used in space, the resolution is directly proportional to the reciprocal of the caliber. The telescope will be converted into a perfectly spherical wave front so that the imaging plane wave front emitted from the distant planet. Angular resolution is limited only by the diffraction image - we can call it the diffraction limit.
Before actually affect the atmosphere and the quality of the telescope will be distorted spherical wave imaging process causing the phase error. Even in the best place of observation, visible light telescopes on the ground can not 超过 angular resolution of 10-20 cm diameter telescope, it is only because of atmospheric turbulence sake. For a four-meter-diameter telescope, so that the spatial resolution of atmospheric turbulence an order of magnitude lower (compared to the diffraction limit), while the center of the lower resolution satellite image 100 times. This stems from the former atmospheric disturbances caused by waves of instability in time and space - also send humans into space Hubble observations of the most important reason - to avoid the effects of atmospheric turbulence. In addition, image quality is good or bad by industrial technology issues and the impact of the wavefront by the mechanical, thermal and optical effects caused by the telescope distorted. |