List of largest infrared telescopes

List of largest infrared telescopes, by diameter of entrance aperture, oriented towards large observatories dedicated to infrared astronomy. Infrared has a number of challenges, especially for ground-based observatories but also in space. The near-infrared is similar to optical telescopes, although the longer wavelength infrared can also be related to aspects of radio and microwave astronomy. A major implication of looking at longer wavelengths are that infrared telescopes have a lower diffraction limit all else being compared to a visible light telescope, because the wavelength of light they are looking is longer. Secondly, infrared is heat, so the telescopes can be much more sensitive to emission of heat.

Atmospheric windows in the infrared: much of this type of light is blocked when viewed from the Earth's surface.

Overall

Infrared observations from Earth's surface are possible in a limited way, but can be very dependent on location and atmospheric conditions. Water vapour blocks much of the infrared band in Earth's atmosphere, although some limited observations are possible and there is a number of infrared focused observatories, which often also view optical visible wavelengths. Sometimes other optical telescopes can make infrared observations if they are equipped with the right detectors, even if they are not dedicated infrared observatories. For ground based observatories the location can make a big difference how much observation his possible.

Name	Image	Effective aperture m (in)	Wavelength Coverage	Site	Year(s)	Refs
VISTA		4.1 m (161″)	0.85 – 2.3 μm	Paranal Obs., Chile	2008	[1]
UKIRT		3.8 m (150″)		Mauna Kea Obs., Hawaii	1978
Herschel Obs.		3.5 m (138″)	60-672 μm	Space, Earth L2	2009-2013	[2]
IRTF		3 m (118″)		Mauna Kea, Hawaii	1979	[3]
SOFIA		2.5 m (98.4 in)		747SP; Stratosphere	2010	[4][5]
Hubble Space Telescope		2.4 m (94.5 inches)	NIR only	Space, Earth orbit]	2009-2013
WIRO		2.3 m (90.6 in)		Jelm mountain, 9656 ft. (2943m)	1977	[6]

Space telescopes only

The mirror of this infrared space telescope is coated with Gold because of its ability to reflect infrared light. Optical telescopes typically have used aluminum or silver.

Infrared observations can see objects hidden in visible light, such as HUDF-JD2 shown.

Name	Effective aperture cm (in)	Wavelength Coverage	Year	Refs
JWST	650 cm	0.6-28.5 μm	2021 (planned)
Herschel Obs.	350 cm (138″)	60-672 μm	2009	[2]
Hubble WFC3	240 cm	0.2-1.7 μm	2009
Spitzer	85 cm	3-180 μm	2003	[4]
Akari	68.5 cm	2-200 μm	2006	[4]
ISO	60 cm	2.5-240 μm	1996	[4]
IRAS	57 cm	5-100 μm	1983	[4]
NEOSM	50 cm	?	Planned	[7]
SWAS	44–70 cm	540 - 610 μm	1998
WISE	40 cm	3-25 μm	2010	[4]
MSX	33 cm	4.3-21 μm	1996
IRT	15.2 cm	1.7-118 μm	1985	[8]
Human Eye	~1 cm	0.39-0.75 μm	-

For comparison

See also

• Lists of telescopes
• Infrared telescope
• List of largest optical reflecting telescopes
• Space Flyer Unit
• Diffuse Infrared Background Experiment (all-sky infrared observation on COBE, launched 1989)

References

1. Emerson, J.P., Sutherland, W.J., McPherson, A.M., Craig, S.C., Dalton, G.B., Ward, A.K. (2005). The Visible & Infrared Survey Telescope for Astronomy. The Messenger
2. Amos, Jonathan (14 June 2009). "ESA launches Herschel and Planck space telescopes". BBC. Retrieved 10 November 2011.
3. IRTF homepage
4. JPL: Herschel Space Observatory: Related Missions
5. Krabbe, Alfred (March 2007). "SOFIA telescope". Proceedings of SPIE: Astronomical Telescopes and Instrumentation. Munich, Germany: SPIE — The International Society for Optical Engineering. pp. 276–281. arXiv:astro-ph/0004253. Bibcode:2000SPIE.4014..276K. doi:10.1117/12.389103.
6. University of Wyoming 2.3-meter Telescope (WIRO)
8. Kent, et al. – Galactic structure from the Spacelab infrared telescope (1992).