Mirror-matl pyrex; flat to 1/4 fringe; parallel to 1 sec of arc; alum coating per mil-m-13508; surface quali type 80-50 per mil-o-13830; 3.5 in. L, 1.87 in. W, 0.97 in. Thk; usable surface 1.75 in. W, 2.75 in. L; mount-matl steel; gray enamel finish; sst screws; azimuth adjustment 4 deg, elevation 2 deg; hardwood carrying case
Fsc Application Data
General purpose laboratory calibration and alignment of surface plates, angle blocks, precision squares, and optical instruments
