An apparatus and method for examining features of a planar, disk-shaped samples on a stage that holdings the sample and has an X-drive, a Y-drive and a .theta.-drive for rotating the stage about a center of rotation defined in the stage coordinates. The sample is placed on the stage such that the center of the sample is substantially aligned with the center of rotation and a measurement assembly is located above the sample to examine the features optically. A scheduling module coordinates the X-drive, the Y-drive and the .theta.-drive with the measurement assembly such that the sample is examined in an even number n of angular sectors defined by a sector angle .THETA. that is the same for each sector. Specifically, the sector angle .THETA. is defined in terms of n as follows:.THETA..times..degree. ##EQU00001## where n=4m and m is an integer, such that a multiple of sector angle .THETA. always includes angles 90.degree. and 180.degree..