Object Record
Images
Metadata
Catalog Number |
83.59.1 |
Collection |
Timepiece |
Other Name |
Astrolabe |
Date |
1973-1993 |
Description |
C 1983 brass This portable instrument, the astrolabe, has varied little in form over the thousand years of its existence, was commonly made out of brass and occasionally drawn or printed on paper glued to wood or pasteboards.It is a very adaptable and versatile instrument that could measure time, day or night, find latitude, some surveying with angular measurements, and the position of the stars could be determined for any given moment in time. It consists of a divided disc that carries a sighting rule called the alidade which rotates around the astrolabe center inside a degree circle. The back plate is engraved with a circular map of the stars. The rete or net is a fretwork plate cut out to show the relative positions of the stars to one another and to the sun's position in the sky in the zodiac circle. Several steps must be taken to find the time. First, the observer places the plate appropriate to the latitude of his position beneater the rete. By using the alidade and the degree scale on the back of the astrolabe, the altitude of the sun or, at night, one of the stars, is measured. Finally, the point diametrically opposite that of the sun's position in the ecliptic is taken and the unequal hour from the scale engraved on the plate beneath the rete is then read. |
Maker |
Elwell Russell |
Place of Origin |
Indiantown, Florida, USA |
Notes |
A 30613 4 slides in slide cabinet 1 X Updated by Cara M. Lower 8/5/14 |