The wavelength range from 91.2 nm (the Lyman limit) to approximately 200 nm; atmospheric absorption of radiation at these wavelengths prevents it from reaching the ground. Space-borne telescopes operating in this region have included the International Ultraviolet Explorer, the Far Ultraviolet Spectroscopic Explorer, and the Hubble Space Telescope. At its short-wavelength end, the far ultraviolet overlaps with the extreme ultraviolet.