A semi-automatic measuring machine

A machine designed to locate automatically a star image on a photographic plate from approximate coordinates on a punched card and to measure and record its position to a micron is described. The main frame of the machine is of granite, as are the x and y coordinate carriages which move on air bearings against granite ways. The system is capable of making measurements continuously over a 10 x 10 inch range by means of a Ferranti moire fringe system, with a least count of one micron.