History of the telescope of the IRAS satellite in 1983 revolutionized infrared astronomy from space. This reflecting telescope which had a mirror, operated for nine months until its supply of coolant (liquid helium) ran out. It surveyed the entire sky detecting 245,000 infrared sources—more than 100 times the number previously known. Although optical telescopes can image the near ultraviolet, the ozone layer in the stratosphere absorbs ultraviolet 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 alternative coatings such as magnesium fluoride or lithium fluoride are used
Ultraviolet biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories. Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting nocturnal insects during faunistic survey studies. Ultraviolet radiation is helpful in the treatment of skin conditions such as psoriasis and vitiligo. Exposure to UVA, while the skin is hyper-photosensitive, by taking psoralens is an effective treatment for psoriasis. Due to