openstartracker is an application for autonomous spacecraft attitude determination from star images. It runs as a long-lived localhost TCP daemon (startracker.py) that accepts commands via socket or stdin, processes images with OpenCV, and returns matched star vectors. The core matching engine is a custom C++ header library (BEAST) wrapped with SWIG, using a Hipparcos-derived constellation database, Morton-coded spatial hashing, an in-place kd-tree, and Bayesian posterior scoring for lost-in-space identification. It also tracks non-star objects across frames and can extrapolate attitude between image times.