Telescope
A telescope is an instrument designed for the observation of remote objects by the collection of electromagnetic radiation. The first known practically functioning telescopes were invented in the Netherlands at the beginning of the 17th century. "Telescopes" can refer to a whole range of instruments operating in most regions of the electromagnetic spectrum.
The name "Telescope" (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei[1][2][3]. In the Starry Messenger Galileo had used the term "perspicillum".
History
The earliest evidence of working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Jacob Metius of Alkmaar[4]. Galileo greatly improved upon these designs the following year. Niccolò Zucchi is credited with constructing the first reflecting telescope in 1616. In 1668, Isaac Newton designed an improved reflecting telescope that bears his name, the Newtonian reflector.
The invention of the achromatic lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857,[5] and aluminized mirrors in 1932.[6] The maximum physical size limit for refracting telescopes is about 1 meter (40 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger then 10 m (33 feet).
The 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937. Since then, a tremendous variety of complex astronomical instruments have been developed.
Other types
Notable telescopes
- Chandra X-ray Observatory
- CHARA (Center for High Angular Resolution Astronomy) array
- Giant Metrewave Radio Telescope
- Great Paris Exhibition Telescope of 1900
- Great Canary Telescope
- Hale telescope 1948, 200" reflector, Mount Palomar
- Hexapod-Telescope
- Hooker Telescope 1917, 100" reflector, Mount Wilson
- Hubble Space Telescope
- IceCube Neutrino Detector
- Isaac Newton Telescope
- Keck telescope
- Leviathan of Parsonstown 1849, 79" reflector, Birr, Ireland
- Lick Observatory
- LIGO
- Lovell Telescope
- Magdalena Ridge Observatory
- McMath-Hulbert Observatory (Solar)
- McMath-Pierce Solar Telescope
- Multiple-Mirror telescope
- Navy Prototype Optical Interferometer
- Overwhelmingly Large Telescope (proposed)
- Parkes Observatory
- Southern African Large Telescope
- Subaru Telescope
- UK Schmidt Telescope
- Very Large Array
- Very Large Telescope
- Westerbork Synthesis Radio Telescope
- William Herschel Telescope
- XMM-Newton
- Yerkes 1897, 40" largest optical refractor
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See also
- Amateur telescope making
- Angular resolution
- Aperture synthesis
- ASCOM open standards for computer control of telescopes
- BOOTES
- Depth of field
- Dynameter
- f-number
- First light
- History of the telescope
- Keyhole problem
- Microscope
- Nimrud lens
- Remote Telescope Markup Language
- Robotic telescope
- Space observatory
- Timeline of telescope technology
- Timeline of telescopes, observatories, and observing technology
Notes
- ^ archive.org "Galileo His Life And Work" BY J. J. FAHIE "Galileo usually called the telescope occhicde or cannocchiale ; and now he calls the microscope occhialino. The name telescope was first suggested by Demisiani in 1612"
- ^ Sobel (2000, p.43), Drake (1978, p.196)
- ^ Rosen, Edward, The Naming of the Telescope (1947)
- ^ galileo.rice.edu The Galileo Project > Science > The Telescope by Al Van Helden "The Hague discussed the patent applications first of Hans Lipperhey of Middelburg, and then of Jacob Metius of Alkmaar... another citizen of Middelburg, Sacharias Janssen had a telescope at about the same time but was at the Frankfurt Fair where he tried to sell it"
- ^ madehow.com - Inventor Biographies - Jean-Bernard-Léon Foucault Biography (1819-1868)
- ^ Bakich sample pages Chapter 2, Page 3 "John Donavan Strong, a young physicist at the California Institute of Technology, was one of the first to coat a mirror with aluminum. He did it by thermal vacuum evaporation. The first mirror he aluminized, in 1932, is the earliest known example of a telescope mirror coated by this technique."
References
- Contemporary Astronomy - Second Edition, Jay M. Pasachoff, Saunders Colleges Publishing - 1981, ISBN 0-03-057861-2
- Template:Harvard reference
- Template:Harvard reference
- Template:Harvard reference
- Sabra, A. I. & Hogendijk, J. P. (2003), The Enterprise of Science in Islam: New Perspectives, MIT Press, pp. 85-118, ISBN 0262194821