The ASTRO APS from Jena-Optronik GmbH is a Star Tracker that has an attitude random error of less than 1 arcsec (across boresight) and 8 arcsec (boresight). This star tracker has an acquisition time of 10 sec after switch ON with a full performance slew rate and acceleration of less than 0.3 deg/sec. It can serve as a star tracker or navigation camera system for up to 18 years lifetime in GEO orbits. The star tracker features an autonomous compensation of White Spots, DSNU, FPN and Dark Current, and full performance with moon in the field of view. It has a field of view of 20 degrees and a sun exclusion angle of 26 degrees. The star tracker requires a power supply of 28-100 V and has a nominal power consumption of 5-12 W. It has a mass of 2 kg and measures 154 x 154 x 237 mm. The star tracker utilizes advanced radiation hard CMOS Active Pixel Sensor detector technology for long-term missions on Telecom, Science and Earth Observation satellites.