Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 17th century
Place India
Material Brass
Inventory no. 33411
Acquisition Presented by A.E. Gunther in 1986

Back



The back contains 15 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.
Sine/Cosine 1/60 of quadrant radius Not numbered  Angle Upper left quadrant (inside circular scales)
Declination Summer solstice - Winter solstice, Zodiacal divisions, equal or unequal Every 10  Arc Upper right quadrant (inside circular scales)
Prayer lines Planet Not numbered  Arc Upper right quadrant (inside circular scales)
Cotangent 0 - 60, Fingers Every 6 fingers Circular, concentric Lower left quadrant of outer circular on back of instrument.
Cotangent 0 - 60, Feet Every 6 feet Circular, concentric Lower right quadrant of outer circular on back of instrument.
Lunar Mansions 0° Aries - 30° Pisces, Lunar mansion 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
Terms 0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal At each term  Inner Circular, concentric half circle inside the VI circle (on mashriqi astrolabes) - covering LL and LR
Faces 0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal At each face  Inner Circular, concentric half circle inside the VII circle (on mashriqi astrolabes) - covering LL and LR
Shadow square 1 - 60, Fingers Every 5 fingers Box Left hand vertical 'face' of the shadow square (in LL)
Shadow square 1 - 60, Fingers Every 5 fingers Box Left hand bottom face of the shadow square (in LL)
Shadow square 1 - 71, Feet Every 10 feet Box Right hand bottom face of the shadow square (in LR)
Shadow square 1 - 71, Feet Every 10 feet 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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