Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date early 18th century
Maker ’Abd al-’Alī
Place Persia
Material Brass
Inventory no. 37940
Acquisition Presented by J. A. Billmeir in 1957

Back


The scales on the back are all incorrect.

The back contains 11 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 None Not numbered  Angle Upper left quadrant (inside circular scales)
Declination None Not numbered  Arc Upper right quadrant (inside circular scales)
Cotangent Fingers Every 5 fingers Circular, concentric Lower right quadrant of outer circular on back of instrument.
Cotangent Feet Every 5 feet Circular, concentric Lower left quadrant of outer circular on back of instrument.
Terms Zodiacal divisions, equal or unequal   Inner Circular, concentric half circle inside the outer circle (on mashriqi astrolabes) - covering LL and LR
Zodiacal signs Zodiacal divisions, equal or unequal   Inner Circular, concentric half circle inside the V circle (on mashriqi astrolabes) - covering LL and LR
Faces Astrological face   Inner Circular, concentric half circle inside the VI circle (on mashriqi astrolabes) - covering LL and LR
Lunar Mansions Lunar mansion   Inner Circular, concentric half circle inside the VII circle (on mashriqi astrolabes) - covering LL and LR
Shadow square None   Box None
Triplicities Zodiacal divisions, equal or unequal   Inner Box Box 'inside' the shadow square. Common site for triplicities, etc.
The back is inscribed:
Transcription Translation Notes Type
العلي عبد صنعه ‘Abd al-‘Ali made this Maker's signature
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