Abstract: A ring shape lighting device, used for lighting the mark around the CCD camera, has a lighting device, a lighting brightness control device, a lighting height control device, a lighting color control device and a controller. The controller controls these devices and detects the marks using the CCD camera, by changing the lighting brightness at 1 percent step from 1 to 100 percent with different combinations of lighting height and lighting color. The device detects the mark contrasts using a contrast detection/determination device and detects the variance using a variance detection/determination device. The device then determines the best lighting condition based on the variance.

Abstract: When a large optical device is incorporated into a large telescope or the like, a support state and a load distribution are different from those when an object to be ground is placed on a workpiece supporting fixture of a processing machine, and a surface shape measured in a state of being mounted on the processing machine is different from a surface shape in an incorporated state. Thus, there has been no apparatus for manufacturing an optical device that is deformed by its own weight.