The 1.3-m McGraw-Hill telescope can be used at either f/7.6 (20.72 arcseconds/mm) or f/13.5 (11.81 arcseconds/mm). Both secondary mirrors are mounted on the same top end, and the observer can flip between them during the night.
All mirrors are made of low expansion Cer-Vit with aluminum overcoating. The primary mirror is 1.32 meters in diameter, but has been masked down to a diameter of 1.27 meters.
The precise longitude of the telescope is -111.6167 degrees, and the latitude is 31.950 degrees. The altitude is 1925.0 meters.
When imaging, the filterbox can hold up to 8 filters. The largest size filter that can be used is 2 inch square, with smaller sizes and formats mounted using special adaptors.
A complete operations manual (from which all of this information was extracted) is kept in the control room.