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The telescope is more a discovery of optical craftsmen than an invention of a scientist. [1] [2] The lens and the properties of refracting and reflecting light had been known since antiquity, and theory on how they worked was developed by ancient Greek philosophers, preserved and expanded on in the medieval Islamic world, and had reached a significantly advanced state by the time of the ...
Typically the circular telescope aperture is split up into an array of pixels in a wavefront sensor, either using an array of small lenslets (a Shack–Hartmann wavefront sensor), or using a curvature or pyramid sensor which operates on images of the telescope aperture. The mean wavefront perturbation in each pixel is calculated.
Comparison of nominal sizes of apertures of the above extremely large telescopes and some notable optical telescopes. An extremely large telescope (ELT) is an astronomical observatory featuring an optical telescope with an aperture for its primary mirror from 20 metres up to 100 metres across, [1] [2] when discussing reflecting telescopes of optical wavelengths including ultraviolet (UV ...
Aperture synthesis is possible only if both the amplitude and the phase of the incoming signal are measured by each telescope. For radio frequencies, this is possible by electronics, while for optical frequencies, the electromagnetic field cannot be measured directly and correlated in software, but must be propagated by sensitive optics and interfered optically.
The Houghton telescope or Lurie–Houghton telescope is a design that uses a wide compound positive-negative lens over the entire front aperture to correct spherical aberration of the main mirror. If desired, the two corrector elements can be made with the same type of glass, since the Houghton corrector's chromatic aberration is minimal.
Aperture synthesis is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and aperture masking interferometry at single reflecting telescopes. Radio telescopes are also used to collect microwave radiation , which has the advantage of being able to pass through the atmosphere and interstellar ...
In a telescope the objective is the lens at the front end of a refracting telescope (such as binoculars or telescopic sights) or the image-forming primary mirror of a reflecting or catadioptric telescope. A telescope's light-gathering power and angular resolution are both directly related to the diameter (or "aperture") of its objective lens or ...
The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft. [ 8 ] Hubble features a 2.4 m (7 ft 10 in) mirror, and its five main instruments observe in the ultraviolet , visible , and near-infrared regions of the electromagnetic ...