High Quality Content by WIKIPEDIA articles! The Vatican Advanced Technology Telescope, aka the VATT, is a 1.8 meter Gregorian telescope observing in the optical and infrared. It is part of the Mount Graham International Observatory. It is situated on Mount Graham in southeast Arizona, and it achieved `first light`, the first starlight to pass through the telescope onto a detector, in 1993. It is operated by the Vatican Observatory, one of the oldest astronomical research institutions in the world, in partnership with The University of Arizona.