Mirror Facets for the VERITAS Telescopes

Each of the VERITAS telescopes has 345 glass facets. These were manufactured by D.O.T.I. (Roundrock, Texas), by slumping and grinding to get the desired optical figure. The facets were alu- minized and anodized at the Whipple Observatory. The reflect ivity, radius of curvature and spot size were measured. The design specifications for reflectivity ( 90% at 320 nm and � 85% between 280 nm and 450 nm), radius of curvature (24 m < ±1%) and spot size (< 10 mm at radius of curvature) were easily met. The aluminizing and anodizing process are described as well as the effects of exposure at the VERITAS site on the reflectivity.