Reaching Submillisecond Accuracy in Stellar Occultations and Artificial Satellite Tracking

In recent years there appeared a need for astronomical observations timed with sub-millisecond accuracy. These include e.g. timing stellar occultations by small, sub-km or fast Near Earth Asteroids, but also tracking artificial satellites at Low Orbit using optical sensors. Precise astrometry of fast-moving satellites, and accurate have parallel needs, requiring reliable time source good knowledge camera delays. Thus an external device that would enable equipment testing, to check if they reach the required accuracy in time. We designed, constructed thoroughly tested New EXposure Timing Analyser (NEXTA): GNSS-based precise timer (Global Navigation Satellite System), allowing 0.1 millisecond, which is order magnitude better than previously available tools. The simple strip blinking diodes, be imaged under test compare internal stamp. Our tests spanned range scientific cameras widely used ground-based satellite tracking. results revealed high reliability both NEXTA most cameras, pointed practically all had bias various level. can serve community, being easily reproducible inexpensive components. provide necessary schemes usage instructions.