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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 ...
The frame of a sextant is in the shape of a sector which is approximately 1 ⁄ 6 of a circle (60°), [3] hence its name (sextāns, sextantis is the Latin word for "one sixth"). "). Both smaller and larger instruments are (or were) in use: the octant, quintant (or pentant) and the (doubly reflecting) quadrant [4] span sectors of approximately 1 ⁄ 8 of a circle (45°), 1 ⁄ 5 of a circle (72 ...
Nocturnal: instrument to determine local time using relative positions of two or more stars in the night sky; Octant: measuring instrument used primarily in navigation; type of reflecting instrument; Optical spectrometer, also known as Spectrograph: instrument to measure the properties of visible light; Orrery: mechanical model of the Solar System
In Arabic texts, the word is translated as ākhidhu al-nujūm (Arabic: آخِذُ ٱلنُّجُومْ, lit. ' star-taker ') – a direct translation of the Greek word. [6] Al-Biruni quotes and criticises medieval scientist Hamza al-Isfahani, who stated: [6] "asturlab is an Arabisation of this Persian phrase" (sitara yab, meaning "taker of the ...
Nocturnal used to determine apparent local time by viewing the Polaris and its surrounding stars. Ring dial or astronomical ring used to measure the height of a celestial body above the horizon. It could be used to find the altitude of the Sun or determine local time. It let sunlight shine through a small orifice on the rim of the instrument.
A nocturnal is an instrument used to determine the local time based on the position of a star in the night sky relative to the pole star. As a result of the Earth's rotation , any fixed star makes a full revolution around the pole star in 23 hours and 56 minutes and therefore can be used as an hour hand .
Allow transit measurements in any direction . Theodolite (Describing a theodolite as a transit may refer to the ability to turn the telescope a full rotation on the horizontal axis, which provides a convenient way to reverse the direction of view, or to sight the same object with the yoke in opposite directions, which causes some instrumental errors to cancel.
The merkhet or merjet (Ancient Egyptian: mrḫt, 'instrument of knowing' [1]) was an ancient surveying and timekeeping instrument. It involved the use of a bar with a plumb line, attached to a wooden handle. [2] It was used to track the alignment of certain stars called decans or "baktiu" in the Ancient Egyptian. When visible, the stars could ...