Torquetum, Replica
name: label: maker
content: L. C. Eichner Instruments
notes: label: Description
content: This is a modern reproduction of a fifteenth century German instrument, designed to allow one to measure the position of a celestial object in celestial coordinates. The brass device has a square base plate with a circle drawn on it which is graduated to 360 degrees by degrees. This base is supported at an angle of about 40 degrees, and represents the equatorial plane. Pivoted at its center is a brass disc that carries the support for a smaller disc 37 cm. in diameter with two circles marked on it. The platform for the smaller disc makes an angle of about 25 degrees with the large disc. It represents the plane of the ecliptic. The outer circle of the smaller disc is graduated into 12 months, each of 30 days. These months are labeled with the names of zodiacal constellations. The inner circle is graduated into 12 months of unequal numbers of days and marked with names of months. Mounted on the disc is a rotating inner disc which has sights at opposite ends of one diameter. This rotating disc also has a support for a disc perpendicular to it, 26 cm. in diameter. The disc perpendicular to the ecliptic is divided into four quadrants and these are divided to degrees. Mounted in front of this disc is a movable semicircular ring divided to degrees. From the diameter of the semicircle, at the center, hangs a string for a brass bob. The bob is 1 cm. in diameter and 2.5 cm. long. When the sight is set on a star, the instrument allows one to read the coordinates of the star in celestial longitude and latitude and to find the right ascension and the altitude.
label: Description
content: References:
label: Description
content: J. Hartmann, "Die aeltesten astronomischen Instrumente," <I>Zeitschrift Instrumentenbunde</I>, vol. 40 (1920) 221-235.
label: Description
content: J. Hartmann, "Die astronomischen Instrumente des Kardinals Nikolaus Cusanus," <I>Abh. Kgl. Ges. Wiss. Goettingen, Math.-Phys. Klasse</I>, N.F. X, no. 6 (1919).
label: Description
content: G.M. Hudson, "Torquetum," <i>Instruments of Science</I>, pp. 623-626.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.327547
label: catalog number
content: 327547
label: accession number
content: 267517
objectType: label: Object Name
content: Torquetum
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: string (overall material)
label: Measurements
content: overall: 65 cm x 38 cm x 42 cm; 25 19/32 in x 14 31/32 in x 16 17/32 in