The GPI ST™ is the basis of many of the GPI and VeriFire family. The addition of motorised zoom and focus and superior camera over the GPI LC allows you to perform visual fringe analysis of flat or spherical surfaces, and transmitted wavefront measurement of optical components and assemblies on an expanded range of parts. Images are displayed on a high-quality 9" monochrome video monitor.

The video monitor also displays ZYGO's QFAS (Quick Fringe Acquisition System) two-spot alignment. Fast and reliable electronic switching (using a hand-held remote) alternates between the "align" and "view" images on the video monitor, making fringe display a snap. Its motorised zoom and focus facilitates easier part measurement over a wider range of part diameters and allows for longer measurement cavities.

The GPI ST requires operator fringe pattern interpretation.