1,25-кратный шаговый проекционный объектив с маской

This is a 1.25x relay optic used for printing on substrates from photo masks. It is corrected for 308nm wavelength which indicates fused silica or quartz optics throughout. The tube assembly is 3 inches in diameter and 21.75 inches long. The objectives have a clear aperture of 48mm. Both ends of the tube include special protective metal cover plates that may secured by button-head cap screws. The lens cells appear to be quite elaborate.