why do optical telescopes work better in space
The Hubble Space Telescope has beamed
hundreds of thousands of images back to Earth over the past two decades. One might call it the most skilled paparazzo, snapping countless images of the stars. Thanks to these images, scientists have been able to determine the age of the universe and shed light on the existence of dark energy. These extraordinary advancements have been possible because the surpass those taken by Earth-based telescopes.
While ground-based observatories are usually located in highly elevated areas with minimal light pollution, they must contend with atmospheric turbulence, which limits the sharpness of images taken from this vantage point. (The effects of atmospheric turbulence are clear to anyone looking at? this is why they appear to twinkle. ) In space, however, telescopes are able to get a clearer shot of everything from exploding stars to other galaxies.
Another disadvantage for ground-based telescopes is that the Earth's atmosphere absorbs much of the infrared and ultraviolet light that passes through it. Space telescopes can detect these waves. Newer ground-based telescopes are using technological advances such as adaptive optics to try to correct or limit atmospheric distortion, but there's no way to see the wavelengths that the atmosphere blocks from reaching Earth, according to the Space Telescope Science Institute (STScI), which manages the Hubble research program.
One downside to like the Hubble is that they are extremely difficult to maintain and upgrade. The Hubble is the first telescope specifically designed to be repaired in space by astronauts, while other space telescopes cannot be serviced at all.
NASA scientists estimate that the telescope will only be able to keep taking pictures for five more years. Refracting Telescopes "refract" (bend) the light through a series of lenses. All others irrespective of the radiation under study, but including optical-wavelength light, are Reflecting Telescopes; in which a large parabolic reflector gathers the radiation over a large area and focuses it onto the detector, maginfying intensity rather than size.
An optical refracting telescope's lens is similarly large for light-gathering power. The magnification is an optical telescope of either type is a second stage. Radio telescopes may be grouped in arrays to give the same effect as a very large single aperture. This reduces the diameter or the reflector, for structural advantages.
- Autor: OpalDecoteau
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