Inspecting device i.e. photoelectric matrix, for inspecting shape of membranous mirror for telescope utilized in levitation technique, has rotary opaque screens bored with openings formed as spiral or radial slits

摘要

The device i.e. photoelectric matrix (7), has rotary opaque screens (8) bored with openings, where lighting beam is centered on an optical axis (2) of a membranous mirror. The openings are formed as spiral slits or radial slits. The radial slits are occulted by an obturator. The obturator comprises a shutter movable around the optical axis. The shutter is rotated to seal the radial slits. The obturator comprises circular slits movable along radius of the radial slits. The circular slit is secured with a tape that is rolled up at and unrolled from an end of the radial slits.