Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date ca. 1700
Maker Khalīl Muḥammad ibn Ḥasan ‘Alī
Place Iṣfahān
Material Brass
Inventory no. 50987
Acquisition Presented by J. A. Billmeir in 1957

Back



The back contains 16 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.
Declination Gemini/Cancer - Sagittarius/Capricorn, Zodiacal divisions, equal or unequal Not numbered  Arc Upper right quadrant (inside circular scales)
Azimuth of Qibla Cities Not numbered  Arc Upper right quadrant (inside circular scales)
Altitude 30 - 42, Degrees of latitude Every 2 degrees Arc Upper right quadrant (inside circular scales)
Sine/Cosine 1/60 of quadrant radius Not numbered  Angle Upper left quadrant (inside circular scales)
Cotangent 0 - 30, Feet Every 5 feet Circular, concentric Lower left quadrant of outer circular on back of instrument.
Cotangent 0 - 40, Fingers Every 5 fingers Circular, concentric Lower right quadrant of outer circular on back of instrument.
Terms 0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal Not numbered  Inner Circular, concentric half circle inside the outer circle (on mashriqi astrolabes) - covering LL and LR
Zodiacal signs Aries - Pisces, Zodiacal sign Not numbered  Inner Circular, concentric half circle inside the V circle (on mashriqi astrolabes) - covering LL and LR
Faces 0° Aries - 30° Pisces, Astrological face Not numbered  Inner Circular, concentric half circle inside the VI circle (on mashriqi astrolabes) - covering LL and LR
Lunar Mansions 0° Aries - 30° Pisces, Lunar mansion Not numbered  Inner Circular, concentric half circle inside the VII circle (on mashriqi astrolabes) - covering LL and LR
Shadow square 0 - 7, Feet Every 1 feet Box Left hand vertical 'face' of the shadow square (in LL)
Shadow square 0 - 7, Feet Every 1 feet Box Left hand bottom face of the shadow square (in LL)
Shadow square 1 - 12, Fingers Every 1 fingers Box Right hand bottom face of the shadow square (in LR)
Shadow square 1 - 12, Fingers Every 1 fingers Box Right hand vertical face of the shadow square (in LR)
Triplicities Zodiacal divisions, equal or unequal Not numbered  Inner Box Box 'inside' the shadow square. Common site for triplicities, etc.
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