A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects.
A large number of observatories have been launched into orbit, and most of them have greatly enhanced our knowledge of the cosmos.
Performing astronomy from the Earth’s surface is limited by the filtering and distortion of electromagnetic radiation due to the Earth’s atmosphere.
This makes it desirable to place astrononomical observation devices into space.
As a telescope orbits the Earth outside the atmosphere it is subject neither to twinkling (distortion due to thermal turbulences of the air) nor to light pollution from artificial light sources on the Earth.
But space-based astronomy is even more important for frequency ranges which are outside of the optic window and the radio window, the only two wavelength ranges of the electromagnetic spectrum that are not severely attenuated by the atmosphere.
For example, X-ray astronomy is nearly impossible when done from the Earth, and has reached its current important stand within astronomy only due to orbiting satellites with X-ray telescopes such as the Chandra observatory or XMM-Newton observatory.
Infrared and ultraviolet are also greatly blocked..
Active optics is a relatively new technology for reflecting telescopes developed in the 1980s, which has more recently enabled the construction of a generation of telescopes with 8 metre primary mirrors.
Active optics works by “actively” adjusting the telescope’s mirrors.
This method is used by, among others, the Nordic Optical Telescope, the New Technology Telescope and the Keck telescopes, as well as all large telescopes built in the last decade.
Most modern telescopes are reflectors, with the primary element being a very large mirror.
Historically, the mirrors had to be very thick to hold its shape to the required accuracy as the telescope travelled across the sky.
A new generation of telescopes built since the 1980s uses instead very thin mirrors, which are too thin to keep themselves rigidly in the correct shape.
Instead, an array of actuators behind the mirror keeps it in an optimal shape.
The telescope may also be segmented into many small mirrors, preventing most of the gravitational distortion that occurs in large, thick mirrors..
European Southern Observatory
The European Southern Observatory (ESO, also more formally the European Organisation for Astronomical Research in the Southern Hemisphere) is an intergovernmental research organisation for astronomy, composed and supported by eleven countries from the European Union plus Switzerland.
Created in 1962, it is famous for building and operating some of the largest and most technologically advanced telescopes in the world, such as the New Technology Telescope (NTT), which was one of the telescopes which pioneered active optics technology, and more recently the VLT (Very Large Telescope), consisting of four 8-meter class telescopes.
In 2005, it obtained the first picture of an exosolar planet, 2M1207b, orbiting a brown dwarf 260 light-years away..
A telescope is an instrument designed for the observation of remote objects.
The term usually refers to optical telescopes, but there are telescopes for most of the spectrum of electromagnetic radiation and for other signal types. An optical telescope gathers and focuses visible light and other electromagnetic radiation.
Telescopes increase the apparent angular size of distant objects, as well as their apparent brightness.
Telescopes work by employing one or more curved optical elements – lenses or mirrors – to gather light or other electromagnetic radiation and bring that light or radiation to a focus, where the image can be observed, photographed or studied.
Optical telescopes are used for astronomy and in many non-astronomical instruments including theodolites, transits, spotting scopes, monoculars, binoculars, camera lenses and spyglasses..
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