#navigation

• 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.
• Outer harbor — A specially designed, deep water area partially enclosed by breakwaters, located at the main entrance of a harbor or downstream of a river port, intended for temporary ship mooring, turning maneuvers, or absorbing wave energy. In a geo-economic sense, it designates a subsidiary port, often a deep-water one, built at the mouth of an estuary to accommodate modern large vessels that cannot navigate to the main inland port.
• Outer roadstead — An area of water located outside the harbor proper, but partially protected naturally or by outer breakwaters, where ships can safely anchor to wait for entrance into port basins, berth availability, or improved weather conditions; outer roadstead. It represents the first secured maritime point of contact prior to entering an outer harbor or inland port.
• Axiometru — An apparatus, technical device, or mechanical or electronic indicator mounted on a ship's bridge, used to continuously and precisely indicate the tilt angle or exact position of the rudder blade relative to the vessel's longitudinal axis. This structural precision instrument is essential for ensuring navigation control, allowing the helmsman to execute delicate steering maneuvers and maintain a stable course.
• Azimuth — The horizontal angle formed between the meridian plane of a location (North direction) and the vertical plane passing through the observed point or target celestial body, measured clockwise from 0° to 360°; a horizontal coordinate element used for spatial orientation, topography, and marine or aerial navigation.
• Azimuth — The horizontal angle measured clockwise (from 0° to 360°) between the North direction of a reference meridian and the direction toward a given point on the Earth's surface or the projection of a celestial body on the horizon.
• Port side — The left side of a ship, vessel, or aircraft, determined when looking forward from the stern towards the bow. In international nautical terminology, this side is symbolically marked at night by red running lights to ensure proper navigation and prevent collisions at sea.