Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 1789/90 (A.H. 1204)
Maker Sayyid ’Abd al-Baqi
Place Persia (?)
Material Brass
Inventory no. 50059
Acquisition Presented by J. A. Billmeir in 1957

Back


The upper right quadrant, where one would expect to find the qibla lines, is blank, suggesting that this instrument was not completed.

The back contains 3 scales of the following types:
Type
(click to view scale details)		 Range & Units Numbered Geometry Location
Altitude 0 - 90, Degrees Every 6 degrees Circular, concentric Upper right quadrant of outer circular on back of instrument.
Altitude 0 - 90, Degrees Every 6 degrees Circular, concentric Upper left quadrant of outer circular on back of instrument.
Cotangent 0 - 30, None Every 5  Circular, concentric Lower left quadrant of outer circular on back of instrument.
Cotangent 0 - 45, None Every 5  Circular, concentric Lower right quadrant of outer circular on back of instrument.
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