| GENERAL CHARACTERISTICS ITEM DESCRIPTION | MATL.-OPTICAL GLASS PER MIL-G-174,CLASS 1,TYPE 517-642,GR B; 5.000 IN. DIA.; THICKNESS VARIES WITH SPHERICAL RADIUS; INNER AND OUTER CENTERS OF CURVATURE TO BE CONCENTRIC TO WITHIN 0.001 IN.; INNER AND OUTER SURFACES SHALL BE ANTI-REFLECTION COATED WITH MAGNESIUM FLOURIDE PER MIL-C-675,COATING OPTIMIZED FOR 1.06 MICRONS |