#heading alignment
- Astrocompass — A high-precision optical or gyroscopic navigation instrument used to determine the direction of travel (heading) and azimuth of a vehicle (ship, aircraft, or spacecraft) by directly observing and automatically tracking the position of known celestial bodies (such as the Sun, Moon, or specific stars). This device is essential in polar regions or space, where classic magnetic compasses become completely ineffective due to Earth's magnetic anomalies or the lack of a reference magnetic field.