Astrolabe Catalogue

 

Small image of complete astrolabe back. Click to enlarge.
Date 1282/3
Maker Ḥasan ibn ‘Alī
Place Cairo
Material Brass
Inventory no. 49861
Acquisition Presented by Lewis Evans in 1924

Back


This side of the plate was silvered, most of which is now rubbing off. In addition to the scales on this plate, there are two tables: 'Know the degree of the sun' and a table of Coptic Months..

The back contains 4 scales of the following types:
Type
(click to view scale details)		 Range & Units Numbered Geometry Location
Altitude 0 - 90, Degrees of arc Every 5 degrees Circular, concentric Upper right quadrant of outer circular on back of instrument.
Altitude 0 - 90, Degrees of arc Every 5 degrees Circular, concentric Upper left quadrant of outer circular on back of instrument.
Sine/Cosine 0 - 70, None Every 5  Angle Upper left quadrant (inside circular scales)
Sine/Cosine 0 - 70, None Every 5  Angle Upper right quadrant (inside circular scales)
Cotangent 0 - 45, Fingers Every 5 fingers Circular, concentric Lower right quadrant of outer circular on back of instrument.
The back is inscribed:
Transcription Translation Notes Type
[inscriptions above left-hand table and in sine graphs] [ pending ] None
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