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 empire on which the sun never sets expression, the sun never sets in the Spanish dominions, but ever shines upon one part or other of them : which, to say truly, is a beam of glory [...]". Thomas Urquhart wrote of "that great Don Philippe, Tetrarch of the world, upon whose subjects the sun never sets." In the German dramatist Friedrich Schiller's 1787 play, "Don Carlos", Don Carlos's father, Philip II, says, "" ("I am called / The richest monarch in the Christian world; / The sun in my dominion never sets."). Joseph Fouché recalled Napoleon saying before the Peninsular War, "Reflect that the sun never sets