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
The Sun Is Often Out on the AllMusic website, by both critics and fans. All songs written by Crispin Hunt except where noted. The Sun Is Often Out The Sun Is Often Out (stylized as THE SUN iS OfTEN oUT) is the debut album by Longpigs, released in 1996 on U2's record label, Mother Records. Five singles were released from the album, initially to little success. The first two - "She Said" and "Jesus Christ" - both failed to crack the UK Top 40, both stalling at No. 67. The third single - "Far" fared a little better, scraping into the Top 40, reaching No.