Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 17th century (?)
Place Turkey
Material Brass
Inventory no. 53307
Acquisition Presented by J. A. Billmeir in 1957

Back



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.
Unequal hours 1 - 6, 1/12 of daylight Not numbered hours Arc half circle inside the VIII circle (on mashriqi astrolabes) - covering LL and LR
Cotangent 0 - 25, Fingers Every 5 fingers Circular, concentric Lower right quadrant of outer circular on back of instrument.
Shadow square 0 - 12, Fingers Every 6 fingers Box Lower right quadrant
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