What, really, is a “space telescope”?

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And why send a telescope into space?

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(Let’s consider the Hubble.)

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For more use the DOOR.

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[MORE]

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    First, the “why?”

    We send telescopes into space (1) to learn more in general about the stars and other stuff out there, and (2) to learn about how  the universe moves and operates, and (3) to learn how and when the universe began (if that’s possible). And by putting a telescope in space (4) we can see things without the distortion of Earth’s atmosphere messing things up. You see, clearer pictures taken in space can be sent electronically to receiving devices on Earth (electronically, something like HD TV comes to your living room). These are generalizations, of course.

    Now some details about Hubble:

    • The Hubble Space Telescope (HST) is a space telescope carried into orbit by a space shuttle in 1990 and remains in operation. A 2.4-meter (7.9 ft) diameter telescope in low Earth orbit, Hubble’s four main instruments observe in the near ultraviolet, visible [that sounds familiar], and near infrared spectra. The telescope is named after the famous astronomer Edwin Hubble who discovered the expansion of the universe.

    • Hubble’s orbit outside the distortion of Earth’s atmosphere allows it to take extremely high-resolution images with almost no background light. Hubble’s Deep Field has recorded some of the most detailed visible-light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.

    • Space telescopes were proposed as early as 1923.  Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, Hubble’s main mirror was found to have been ground incorrectly, compromising the telescope’s capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.

    • Hubble is the only telescope designed to be serviced in space by astronauts.

    • The telescope is now expected to function until at least 2014, and possibly 2020. Its scientific successor, the James Webb Space Telescope (JWST), is currently scheduled to be launched in 2018.

[The above bulleted details, adapted and modified, ride heavily upon summary data provided by Wikipedia.]