A joint US–Italian–German telescope consisting of twin 8.4-m mirrors on a common mounting at Mount Graham International Observatory. The first mirror began operation in 2005, with the second following in 2008. The telescope has the light-gathering area of a single 11.8-m reflector. The mirror centres are 14.4 m apart. The LBT has its headquarters at Tucson, Arizona.
http://www.lbto.org/index.htm Official telescope website.
https://www.jpl.nasa.gov/missions/large-binocular-telescope-interferometer-lbti/