"Kvadrant"
The quadrant is an early prototype of the sextant, an astronomical instrument for determining the height of luminaries. A quadrant consists of a quarter-circle dial plate for reading angles and a grid (or telescope) for fixing the angle, attached to this plate at one end. A quadrant is an astronomical instrument used to measure the height of celestial bodies. It consists of a quarter circle, divided into degrees and smaller parts, and is set in a vertical plane. In the center of the arc rotates a diopter or telescopic ruler. The position of zero (the beginning of the count, usually from the nadir) was determined by a line with a weight in a container of water or oil, and the position of the alidade or tube when aiming at the observed object was calculated using a vernier. For portable and permanent observatories, it is in the forms fixed on the stone walls of the observatory building, stationary in the meridian plane.