Astrolabe Catalogue

 

Small image of astrolabe back with rules or alidades removed. Click to enlarge.
Date 17th century
Place India (?)
Material Brass
Inventory no. 33796
Acquisition Presented by A. E. Gunther in 1986

Back



The back contains 12 scales of the following types:
Type
(click to view scale details)
Range & Units Numbered Geometry Location
Altitude 0 - 90, Degrees of arc Every 6 degrees Circular, concentric Upper right quadrant of outer circular on back of instrument.
Altitude 0 - 90, Degrees of arc Every 6 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 24 - 36, Degrees of latitude Every line 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 - 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.
Shadow square 0 - 12, Fingers Every 2 fingers Box Left hand vertical 'face' of the shadow square (in LL)
Shadow square 0 - 12, Fingers Every 2 fingers Box Left hand bottom face of the shadow square (in LL)
Shadow square 0 - 7, Feet Every 2 feet Box Right hand bottom face of the shadow square (in LR)
Shadow square 0 - 7, Feet Every 2 feet Box Right hand vertical face of the shadow square (in LR)
Lunar Mansions 0° Aries - 30° Pisces, Lunar mansion   Inner Circular, concentric half circle inside the outer circle (on mashriqi astrolabes) - covering LL and LR
Zodiacal signs Aries - Pisces, Zodiacal sign   Inner Circular, concentric half circle inside the V circle (on mashriqi astrolabes) - covering LL and LR
MHS Home | Contact Us | ©2006 Museum of the History of Science