The Vatican Observatory Research Group (VORG) operates the 1.8m Alice P. Lennon Telescope with its Thomas J. Bannan Astrophysics Facility, known together as the Vatican Advanced Technology Telescope (VATT), at the Mount Graham International Observatory (MGIO) in southeastern Arizona where sky conditions are among the best in the world and certainly the Continental United States.

The Vatican Advanced Technology Telescope (VATT) truly lives up to its name. Its heart is a 1.8-m f/1.0 honeycombed construction, borosilicate primary mirror. This was manufactured at the University of Arizona Mirror Laboratory, and it pioneered both the spin-casting techniques and the stressed-lap polishing techniques of that Laboratory which are being used for telescope mirrors up to 8.4-m in diameter. The primary mirror is so deeply-dished that the focus of the telescope is only as far above the mirror as the mirror is wide, thus allowing a structure that is about three times as compact as the previous generation of telescope designs.

The 0.38-m f/0.9 Zerodur concave secondary mirror was manufacted by the Space Optics Research Laboratory (Chelmsford, MA). Its mount allows control of its focus and positioning to 0.1 microns, an accuracy needed for such a fast optical system.

The telescope mount is of altitude-azimuth design and was manufactured by L&F Industries (Huntington Park, CA). It features direct drive motors on the two axes, leading to a very compact and rigid mount. The compactness allows a telescope that is very stable in a high wind and easily repositioned on the sky. It also means that a small dome can be used and so the distortions in an image produced by air surrounding a telescope can be minimized.

The building in which the telescope is housed is designed to isolate thermally the ambient temperature in the dome from the heated observing room and living quarters. This isolation is achieved by using the section between the dome and the main facility as a thermal barrier and by exhausting air from this section and from the dome out from the north and mainly downwind side of the building.

Tours of Mount Graham International Observatory, including the VATT, are run on Saturdays from mid-May to mid-November (weather-permitting) from Discovery Park out of Safford.

Both observing time and responsibility for VATT are shared with the University of Arizona on a 75% VORG, 25% Arizona basis. Limited resources prevent VATT from being a visitor observatory, but collaborations are welcomed by VORG, especially when suitable instrumentation is provided for shared use at VATT.

For instance, a three-year agreement was made by the Vatican Observatory with the University of Notre Dame, Indiana (UND), for an Association which provided the UND Department of Physics with 20 nights on VATT per annum.