The Large Binocular Telescope (LBT) is a pair of two 8.4 meter reflector telescopes on Mount Graham (3221 m) in Arizona. The twin reflectors give it both light-capturing capability and ability to capture fine detail through optical interferometry (in that case, called the Large Binocular Telescope Interferometer or LBTI) or to carry out different observations two instruments simultaneously. One reflector has been in production since 2005 and the second since 2008. The reflectors are mounted together and use adaptive optics. Instruments:
Some of these instruments planned for both reflectors currently are in place only on one.