Other wavelengths History of the telescope

1 other wavelengths

1.1 radio telescopes
1.2 infrared telescopes (700 nm/ 0.7 µm – 1000 µm/1 mm)
1.3 ultra-violet telescopes (10 nm – 400 nm)
1.4 x-ray telescopes (0.01 nm – 10 nm)
1.5 gamma-ray telescopes (less 0.01 nm)

other wavelengths

the twentieth century saw construction of telescopes produce images using wavelengths other visible light starting in 1931 when karl jansky discovered astronomical objects gave off radio emissions; prompted new era of observational astronomy after world war ii, telescopes being developed other parts of electromagnetic spectrum radio gamma-rays.

radio telescopes


the 250-foot (76 m) lovell radio telescope @ jodrell bank observatory.

radio astronomy began in 1931 when karl jansky discovered milky way source of radio emission while doing research on terrestrial static direction antenna. building on jansky s work, grote reber built more sophisticated purpose-built radio telescope in 1937, 31.4-foot (9.6 m) dish; using this, discovered various unexplained radio sources in sky. interest in radio astronomy grew after second world war when larger dishes built including: 250-foot (76 m) jodrell bank telescope (1957), 300-foot (91 m) green bank telescope (1962), , 100-metre (330 ft) effelsberg telescope (1971). huge 1,000-foot (300 m) arecibo telescope (1963) large fixed natural depression in ground; central antenna can steered allow telescope study objects twenty degrees zenith. however, not every radio telescope of dish type. example, mills cross telescope (1954) example of array used 2 perpendicular lines of antennae 1,500 feet (460 m) in length survey sky.

high-energy radio waves known microwaves , has been important area of astronomy ever since discovery of cosmic microwave background radiation in 1964. many ground-based radio telescopes can study microwaves. short wavelength microwaves best studied space because water vapor (even @ high altitudes) weakens signal. cosmic background explorer (1989) revolutionized study of microwave background radiation.

because radio telescopes have low resolution, first instruments use interferometry allowing 2 or more separated instruments simultaneously observe same source. long baseline interferometry extended technique on thousands of kilometers , allowed resolutions down few milli-arcseconds.

a telescope large millimeter telescope (active since 2006) observes 0.85 4 mm (850 4,000 µm), bridging between far-infrared/submillimeter telescopes , longer wavelength radio telescopes including microwave band 1 mm (1,000 µm) 1,000 mm (1.0 m) in wavelength.

infrared telescopes (700 nm/ 0.7 µm – 1000 µm/1 mm)

although infrared radiation absorbed atmosphere, infrared astronomy @ wavelengths can conducted on high mountains there little absorption atmospheric water vapor. ever since suitable detectors became available, optical telescopes @ high-altitudes have been able image @ infrared wavelengths. telescopes such 3.8-metre (150 in) ukirt, , 3-metre (120 in) irtf — both on mauna kea — dedicated infrared telescopes. launch of iras satellite in 1983 revolutionized infrared astronomy space. reflecting telescope had 60-centimetre (24 in) mirror, operated 9 months until supply of coolant (liquid helium) ran out. surveyed entire sky detecting 245,000 infrared sources—more 100 times number known.

ultra-violet telescopes (10 nm – 400 nm)

although optical telescopes can image near ultraviolet, ozone layer in stratosphere absorbs ultraviolet radiation shorter 300 nm ultra-violet astronomy conducted satellites. ultraviolet telescopes resemble optical telescopes, conventional aluminium-coated mirrors cannot used , alternative coatings such magnesium fluoride or lithium fluoride used instead. orbiting solar observatory satellite carried out observations in ultra-violet 1962. international ultraviolet explorer (1978) systematically surveyed sky eighteen years, using 45-centimetre (18 in) aperture telescope 2 spectroscopes. extreme-ultraviolet astronomy (10–100 nm) discipline in own right , involves many of techniques of x-ray astronomy; extreme ultraviolet explorer (1992) satellite operating @ these wavelengths.

x-ray telescopes (0.01 nm – 10 nm)

x-rays space not reach earth s surface x-ray astronomy has conducted above earth s atmosphere. first x-ray experiments conducted on sub-orbital rocket flights enabled first detection of x-rays sun (1948) , first galactic x-ray sources: scorpius x-1 (june 1962) , crab nebula (october 1962). since then, x-ray telescopes (wolter telescopes) have been built using nested grazing-incidence mirrors deflect x-rays detector. of oao satellites conducted x-ray astronomy in late 1960s, first dedicated x-ray satellite uhuru (1970) discovered 300 sources. more recent x-ray satellites include: exosat (1983), rosat (1990), chandra (1999), , newton (1999).

gamma-ray telescopes (less 0.01 nm)

gamma rays absorbed high in earth s atmosphere gamma-ray astronomy conducted satellites. gamma-ray telescopes use scintillation counters, spark chambers , more recently, solid-state detectors. angular resolution of these devices typically poor. there balloon-borne experiments in 1960s, gamma-ray astronomy began launch of oso 3 satellite in 1967; first dedicated gamma-ray satellites sas b (1972) , cos b (1975). compton gamma ray observatory (1991) big improvement on previous surveys. high-energy gamma-rays (above 200 gev) can detected ground via cerenkov radiation produced passage of gamma-rays in earth s atmosphere. several cerenkov imaging telescopes have been built around world including: hegra (1987), stacee (2001), hess (2003), , magic (2004).