An infrared telescope is a
telescope that uses
infrared light to detect celestial bodies. Infrared light is one of several types of radiation present in the
electromagnetic spectrum.
All celestial objects with a temperature above
absolute zero emit some form of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
. In order to study the universe, scientists use several different types of telescopes to detect these different types of emitted radiation in the electromagnetic spectrum. Some of these are
gamma ray,
x-ray,
ultra-violet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...
, regular
visible light (optical), as well as infrared telescopes.
Leading discoveries
There were several key developments that led to the invention of the infrared telescope:
* In 1800,
William Herschel discovered infrared radiation.
* In 1878,
Samuel Pierpoint Langley
Samuel Pierpont Langley (August 22, 1834 – February 27, 1906) was an American aviation pioneer, astronomer and physicist who invented the bolometer. He was the third secretary of the Smithsonian Institution and a professor of astronomy a ...
created the first
bolometer. This was a very sensitive instrument that could electrically detect incredibly small changes in temperature in the infrared spectrum.
* Thomas Edison used an alternative technology, his
tasimeter, to measure heat in the sun's
corona during the
solar eclipse of July 29, 1878.
* In the 1950s, scientists used lead-sulfide detectors to detect the infrared radiation from space. These detectors were cooled with
liquid nitrogen.
* Between 1959 and 1961,
Harold Johnson created near-infrared
photometers which allowed scientists to measure thousands of stars.
* In 1961,
Frank Low invented the first
germanium bolometer. This invention, cooled by
liquid helium, led the way for current infrared telescope development.
[Timeline](_blank)
Caltech
Infrared telescopes may be ground-based, air-borne, or
space telescopes. They contain an infrared camera with a special solid-state infrared detector which must be cooled to
cryogenic temperatures.
Ground-based telescopes were the first to be used to observe outer space in infrared. Their popularity increased in the mid-1960s. Ground-based telescopes have limitations because
water vapor in the Earth's atmosphere absorbs infrared radiation. Ground-based infrared telescopes tend to be placed on high mountains and in very dry climates to improve visibility.
In the 1960s, scientists used balloons to lift infrared telescopes to higher altitudes. With balloons, they were able to reach about up. In 1967, infrared telescopes were placed on rockets.
These were the first air-borne infrared telescopes. Since then, aircraft like the
Kuiper Airborne Observatory
The Gerard P. Kuiper Airborne Observatory (KAO) was a national facility operated by NASA to support research in infrared astronomy. The observation platform was a highly modified Lockheed C-141A Starlifter jet transport aircraft (s/n: 6110, re ...
(KAO) have been adapted to carry infrared telescopes. A more recent air-borne infrared telescope to reach the stratosphere was NASA's
Stratospheric Observatory for Infrared Astronomy (SOFIA) in May 2010. Together, United States scientists and the German Aerospace Center scientists placed a 17-ton infrared telescope on a
Boeing 747 jet airplane.
Placing infrared telescopes in space completely eliminates the interference from the Earth's atmosphere. One of the most significant infrared telescope projects was the
Infrared Astronomical Satellite (IRAS) that launched in 1983. It revealed information about other galaxies, as well as information about the center of our galaxy the Milky Way.
NASA presently has solar-powered spacecraft in space with an infrared telescope called the
Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2 ...
(WISE). It was launched on December 14, 2009.
[Griggs, B. (2009, December 14) NASA launches infrared telescope to scan entire sky. ''Cable News Network''. Retrieved from http://www.cnn.com/2009/TECH/space/12/14/wise.spacecraft.launch/index.html]
Selective comparison
The wavelength of visible light is about 0.4 μm to 0.7 μm, and 0.75 μm to 1000 μm (1 mm) is a typical range for
infrared astronomy,
far-infrared astronomy
Far-infrared astronomy is the branch of astronomy and astrophysics that deals with objects visible in far-infrared radiation (extending from 30 μm towards submillimeter wavelengths around 450 μm).
In the far-infrared, stars are not especi ...
, to
submillimetre astronomy.
Infrared telescopes
Ground based :
*
Infrared Telescope Facility
The NASA Infrared Telescope Facility (NASA IRTF) is a telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. It was first built to support the Voyager missions and is now the US national facility ...
, Hawaii, 1979–
*
Gornergrat Infrared Telescope
The Telescopio InfraRosso del Gornergrat (TIRGO), or the Gornergrat Infrared Telescope, was located on the northern tower of the Kulm Hotel at Gornergrat ( altitude) near Zermatt, Switzerland. It was a Cassegrain telescope with a tip-tilt corre ...
, 1979–2005
*
Infrared Optical Telescope Array, 1988–2006
*
United Kingdom Infrared Telescope
The United Kingdom Infra-Red Telescope (UKIRT) is a 3.8 metre (150 inch) infrared reflecting telescope, the second largest dedicated infrared (1 to 30 micrometres) telescope in the world. It is located on Mauna Kea, Hawai'i as part of Mau ...
, 1979–
*
Wyoming Infrared Observatory, 1977-
Airborne:
*
Kuiper Airborne Observatory
The Gerard P. Kuiper Airborne Observatory (KAO) was a national facility operated by NASA to support research in infrared astronomy. The observation platform was a highly modified Lockheed C-141A Starlifter jet transport aircraft (s/n: 6110, re ...
(KAO), 1974-1995
*
Stratospheric Observatory for Infrared Astronomy (SOFIA), 2010-2022
Space based:
*
Infrared Astronomical Satellite, 1983
*
Spitzer Space Telescope, 2003-2020
*
Herschel Space Observatory, 2009-2013
*
Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2 ...
(WISE), 2009-
*
Nancy Grace Roman Space Telescope (formerly WFIRST)
*
James Webb Space Telescope (JWST), 2021-
See also
*
Infrared astronomy
*
List of largest infrared telescopes
*
List of telescope types
The following are lists of devices categorized as types of telescopes or devices associated with telescopes. They are broken into major classifications with many variations due to professional, amateur, and commercial sub-types. Telescopes can be ...
Notes
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System
Telescope types
Infrared imaging