14th century astronomy relied on the astrolabe and other complex tools.
Astronomy in the 14th century was still based on the theories of the ancient astronomer Ptolemy as described in his classic work "The Almagest." The primary use of astronomy was to calculate the correct dates for holy days such as Easter, or the proper time for planting crops. Because the theories of Ptolemy were not sufficient for these important tasks, astronomers used several observational tools to help them with their work.
The Astrolabe
The Whipple Museum of the History of Science preserves an English astrolabe from the 14th century. The astrolabe looks like a brass circle with various designs on the surface. It is set to be used at 52 degrees latitude, most likely in the city of London. It has 41 pointers with the names of different stars, and there is a set of concentric circles on the back for calculations of saint's days and other festivals. The astrolabe could also be used to measure buildings or tell the time of day.
The Astrolabe Quadrant
The astrolabe quadrant was a kind of portable astrolabe. It was only a quarter of a circle rather than a full circle as on an astrolabe proper. The British Museum is in possession of a 14th century astrolabe quadrant -- one of only eight known examples of medieval astrolabe quadrants known to survive.
Celestial and Armillary Spheres
Medieval astronomers also used various tools to model the heavens and the stars as they understood them. A celestial sphere was a three-dimensional model of the Ptolemaic universe in the form of a globe showing the constellations and the stars. The armillary sphere was a set of rings representing the equator, meridians and other important circles found in a celestial sphere.
The Torquetum
The torquetum was a complicated tool of medieval astronomy, made out of flat disks set at different angles to each other. The torquetum could be used to make measurements relating to the equator, the horizon and the ecliptic, and to make conversions between different astronomical observations. It functioned as a kind of analog computer.
Tags: 14th century, 14th century astrolabe, also used, celestial sphere, century astrolabe
