==== General Information on the VATT ====

Optical System : aplanatic Gregorian, f/9\\
Focal Length : 16.48 m\\
Primary Mirror : f/1.0, Diameter 1.83 meters\\
Secondary Mirror : f/0.9, Diameter 0.38 meters\\
Back Focal Distance : 50.80 mm (effective)\\
Vignetting-Free Field : 72 mm diameter (15 arcmin)\\
Image Scale : 12.52 arcsec/mm\\
Image quality : 0.1 arcsec throughout 6.8 arcmin diameter flat FOV\\
Mount : altitude-azimuth with derotator

==== Geographical Location of VATT ====

Latitude : 32° 42' 04.69" N\\
Longitude : 109° 53' 31.25" W\\
Altitude : 3191 meters\\
Driving time from Tucson : 3.5 hours in good conditions\\
IAU Observatory Code number : 290

==== Sky Conditions at VATT ====

The sky surface brightness for low-airmass (sec z < 1.2) observations averaged 22.00, 22.53, 21.49, and 20.88 mag arcsec2 in U, B, V, and R, respectively. These were measured during relatively high solar activity. The darkest run achieved 21.72 in V, close to theoretical minimum of 22.0 mag arcsec2.

The FWHM seeing for median R-band focus images per run ranged from 0.97" to 2.15", with values occasionally as low as 0.65". While this is very good, please note that the VATT's height and location do not give the best seeing achievable at MGIO.

(These values were determined by Violet Taylor, ASU)

==== Computer Systems at VATT ====

**HP Server System and Terminals**
running on a 1 gigabit private network with a TCP/IP link to the Steward Obs. network via microwave connection

**VME** instrument computer running VxWorks

**Linux** for TCS interface, Xephem utility, and autoguider control

**IRAF** reduction software and AzCam data aquisition software