Simple Method for Measuring Wedge Angle of Transparent Plates

A simple set-up for measuring wedge angle of transparent wedge plates has been described. The accuracy of the measurement in the wedge angle is better than 10 arc-sec. The method is found to be useful for measuring wedge angles in the range of 4 arc-min-30 arc-min. The method can also be used for quick identi¬fication of various glass materials. The method will find application in the fabrication of standard wedge plates which are needed in the calibration of autocollimators and Angle Dekkors. The basic equipment for the set¬up is a low power He-Ne laser, microscope objective, telescope doublet, pinhole and travelling microscope.