University of Arizona, who cast mirrors with a honeycomb structure in the interior of a rotating oven. This made it possible to replace the six mirrors with a single 6.5-meter one. The original building and part of the structure could be reused. The new mirror was the first of its size to be cast and polished in the Steward Observatory Mirror Laboratory. The updated MMT, its name no longer an acronym, was rededicated on 20 May 2000. In late 2002, a novel deformable secondary mirror was added to the telescope. While other adaptive optics designs do their corrections with additional mirrors, minimizing the number of warm surfaces in the light path produces better results in infrared wavelengths. The MMT AO system contributed to the design of the Large Binocular Telescope, which achieved record breaking Strehl ratios with its AO system in 2010. From 2004 to 2010, approximately 8% of MMT observing time was made accessible to the entire astronomical community via the US National Science Foundation's Telescope System Instrumentation Program (TSIP), administered by the National Optical Astronomy Observatory (NOAO). See also Massive Monolithic Telescope A telescope made from a single piece of glass List of astronomical observatories List of largest optical reflecting telescopes List largest optical telescopes in the continental United States References External links The MMT Observatory MMT adaptive optics home page Mount Hopkins Clear Sky Clock Forecast of observing conditions. Smithsonian Astrophysical Observatory (SAO) University of Arizona's Steward Observatory University of Arizona Astronomical observatories in Arizona Buildings and structures in Santa Cruz County, Arizona Fred Lawrence Whipple Observatory 1979 establishments in Arizona