Plate from 18th century encyclopedia showing an illustration of an astronomical quadrant. A quadrant is an instrument that is used to measure angles u
Plate from 18th century encyclopedia showing an illustration of an astronomical quadrant. A quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers. The geometric quadrant is a quarter-circle panel usually of wood or brass. Markings on the surface might be printed on paper and pasted to the wood or painted directly on the surface. Brass instruments had their markings scribed directly into the brass. They were not graduated in degrees but rather had the latitudes of the most common destinations directly scribed on the limb. .
Size: 4565px × 6884px
Photo credit: © DAVID PARKER/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: astrolabe, astronomical, astronomy, brass, encyclopedia, illustration, latitude, longitude, muslim, ptolemy, quadrant, quarter-circle, wood
