Anderson Mesa, Arizona, as a Site for an Optical Array

From measurements of cloud cover, seeing profiles, and microthermal properties, Anderson Mesa, near Flagstaff, Arizona, has been evaluated as a potential site for an optical interferometric array. From satellite cloud measurements, northern Arizona was found to have experimental clearer skies than those of southern Arizona and New Mexico during 1984-87, with an expected lower frequency and extent of monsoon-related activity. Using a simple and inexpensive system for measuring instantaneous FWHM of stellar images, the seeing at Anderson Mesa was determined to be well represented by the statistics at the nearby USNO flagstaff Station from which a median seeing of 1.2 arcsec FWHM has been reported. Limited microthermal measurements indicate that Anderson Mesa is rather similar to Mount Graham where tree cover plays a significant role. Anderson Mesa is concluded to be a highly suitable site for an optical array.