ASTROS - A sub-arcsec CCD star tracker

The design and application of ASTROS (Advanced Star and Target Reference Optical Sensor) are described, with emphasis on performance test results acquired with a prototype system. The ASTROS tracker provides extremely precise measurements of star image coordinates as inputs to the Image Motion Compensation (IMC) system used to stabilize the science instrument focal planes. Performance levels achieved are dramatic improvements over the levels achieved with image dissector designs with comparable fields of view.