(focus control: 0.1 micrometre) The heart of the telescope is an f/1.0 honeycombed construction, borosilicate primary mirror.

In addition, the skies above Mount Graham are among the most clear, steady, and dark in the continental North America.

Among the results from this telescope have been the discovery of MACHOs in the Andromeda Galaxy; the validation of the Stromvil photometric filter system; evidence for how the shape and dimensions of galaxies have changed over the age of the universe; discovery of the first binary 'Vesta chip' asteroid; and the characterization and classification by visible colors of some 100 trans-Neptunian objects, most of them fainter than magnitude 21.

The government of the Vatican City State supports the Vatican Observatory staff and regular research costs, but the cost to build and maintain the VATT itself has come from private donors: the major donors supporting the construction of the VATT were Fred and Alice P. Lennon and Thomas J. Bannan.

Benefactors to the Vatican Observatory Foundation continue to support the operating costs of the VATT.