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The Sextant reading is known as the 'Sextant Altitude'. This is corrected by use of tables to a 'True Altitude'. The actual declination and hour angle of the celestial body are found from astronomical tables for the time of the measurement and together with the 'True Altitude' are put into a formula with the assumed latitude.
Sextant. A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation . The estimation of this angle, the altitude, is known as sighting or ...
A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...
These instruments differ substantially from a navigator's sextant in that the latter is a reflecting instrument. The navigator's sextant uses mirrors to bring the image of the sun, moon or a star to the horizon and measure the altitude of the object. Due to the use of the mirrors, the angle measured is twice the length of the instrument's arc.
Kamal (navigation) A simple wooden kamal. A kamal, often called simply khashaba (wood in Arabic), [1] is a celestial navigation device that determines latitude. The invention of the kamal allowed for the earliest known latitude sailing, [2] and was thus the earliest step towards the use of quantitative methods in navigation. [3]
Sight reduction. In astronavigation, sight reduction is the process of deriving from a sight (in celestial navigation usually obtained using a sextant) the information needed for establishing a line of position, generally by intercept method . Sight is defined as the observation of the altitude, and sometimes also the azimuth, of a celestial ...
This is a didactic animation to illustrate the use of the marine sextant to measure the Altitude (astronomy) of the Sun at sea. A detailed explanation of the frames is in the image file. The animation appears in the article sextant. Image created by Joaquim Alves Gaspar. Nominate and support. - Alvesgaspar 11:28, 31 October 2006 (UTC) Comment ...
Meridian altitude is the simplest calculation of celestial navigation, in which an observer determines his latitude by measuring the altitude of an astronomical object at the time of its meridian contact. A meridian contact is the moment when the object contacts the observer's meridian, i.e. the imaginary line running north–south and through ...