IR Telescopes Need relatively large objectives for reasonable resolution at infrared wavelengths. Need cooling to reduce thermal background “noise”

U.K. Infrared Telescope Hawaii 3.8 metre objective observing between 1 micron and 30 microns. This is the near infrared. The telescope's optical quality is good enough to provide images which, in sharpness, are close to the "diffraction limit“ at wavelengths of 2 microns or longer (0.11 arc sec across the width of a point source image). In good atmospheric conditions (good seeing) images of stars less than 2.5 times bigger than this limit have been seen.

SIRTF ( The Space Infrared Telescope Facility) Mirror size 85cm For wavelengths between 10 microns and 1000 micron As SIRTF's own components will emit some infrared, its instruments will be super-cooled to near absolute zero, using a tank of liquid helium. SIRTF will also sit several million km away Earth's infrared "glow" Infrared radiation can penetrate gas and dust clouds, giving SIRTF a clearer view of galaxies and the formation of stars and planets. SIRTF will also look deep into cosmic history. As the Universe expands, radiation emitted by stars and galaxies since the beginning of time is "stretched" to become infrared. SIRTF will be able to see this.

UV telescopes UV telescopes reveal a wealth of information about hot and energetic processes in astronomical objects. This is because the hotter an object is, the more energy it radiates at short wavelengths. UV radiation has shorter wavelengths than visual light, so hot objects are brighter in the UV than in the visual. For example, a hot star like Rigel (the blue-white star that forms Orion's left foot) emits much more UV radiation than the SunRead more:

UV telescopes Although optical telescopes can image the near ultraviolet, the ozone layer in the stratosphere absorbs UV radiation shorter than 300 nm so most ultra-violet astronomy is conducted with satellites. Ultraviolet telescopes resemble optical telescopes, but conventional aluminium coated mirrors cannot be used and alternatives coatings such as magnesium fluoride or lithium fluoride are used instead.

X-ray telescopes The Chandra X-ray observatory. X ray telescopes view high energy events X-ray telescopes must be very different from optical telescopes. Because of their high-energy, X-ray photons penetrate into a mirror in much the same way that bullets slam into a wall. Likewise, just as bullets ricochet when they hit a wall at a grazing angle, so too will X-rays ricochet off mirrors. The mirrors have to be shaped and aligned nearly parallel to incoming X-rays. Thus they look more like glass barrels than the familiar dish shape of optical telescopes.

http://chandra. harvard. edu/resources/animations/mirror_comparison_lg http://chandra.harvard.edu/resources/animations/mirror_comparison_lg.mov