#celestial navigation

• Almucantar — Small circles on the celestial sphere parallel to the horizon, used to measure and determine equal altitudes of celestial bodies above the horizon line. This geometric and astronomical concept is fundamental in classical navigation, allowing the precise localization of an observer's position by determining the intersections of angular coordinates of stars.
• 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.
• Astrocompass — The modern synonymous variant of the term astrocompass; a mechanical, optical, or electronic instrument used to determine true north, a vehicle's heading, and azimuth by directly sighting and tracking celestial bodies. This device plays a crucial role in high-altitude, high-precision aerial or maritime navigation, functioning as an independent redundant system in the event of magnetic or electronic GPS equipment failure.
• Astrodome — A transparent, hemispherical dome or cupola made of optical glass or durable plexiglass, mounted on the upper fuselage of an aircraft (especially 20th-century bombers and transport planes) or on a terrestrial structure. This structural element allowed the flight navigator to use a sextant or astrocompass to determine the position by observing celestial bodies, while in architecture it designates the rotating dome of a small astronomical observatory.
• Astrolabe — An ancient and medieval high-precision astronomical and navigational instrument, consisting of a graduated metal disc equipped with a movable alidade for sighting, used to determine the position of celestial bodies, measure the altitude of stars above the horizon, and calculate local time or latitude. This complex structure, often considered an early analog computer, allowed navigators and astronomers to solve complex spherical trigonometry problems through the stereographic projection of the celestial sphere.
• Astronavigation — The science, technique, or method of guiding and determining the position, trajectory, and speed of a vehicle (maritime ship, aircraft, or spacecraft) through astronomical observations performed on celestial bodies (Sun, Moon, stars, or reference planets). In the context of modern spaceflight, it represents an essential pillar of astrodynamics, utilizing stable optical sensors (star trackers) for the autonomous orientation of interplanetary probes when ground guidance signals are unavailable.