The back contains 13 scales of the following types:
Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
---|---|---|---|---|
Altitude | 0 - 90, Degrees | Every 5 degrees | Circular, concentric | Upper right quadrant of outer circular on back of instrument. |
Altitude | 0 - 90, Degrees | Every 5 degrees | Circular, concentric | Upper left quadrant of outer circular on back of instrument. |
Declination | Summer solstice - Winter solstice, Zodiacal divisions, equal or unequal | Not numbered | Arc | Upper right quadrant (inside circular scales) |
Altitude of noon sun | 26 - 47, Degrees | Every 3 degrees | Arc | Upper right quadrant (inside circular scales) |
Azimuth of Qibla | Cities | Not numbered | Arc | Upper right quadrant (inside circular scales) |
Cotangent | 0 - 35, Feet | Every 5 feet | Circular, concentric | Lower left quadrant of outer circular on back of instrument. |
Cotangent | 0 - 45, Fingers | Every 5 fingers | Circular, concentric | Lower right quadrant of outer circular on back of instrument. |
Zodiacal signs | Aries - Pisces, Zodiacal sign | Not numbered | Inner Circular, concentric | half circle inside the outer 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 V circle (on mashriqi astrolabes) - covering LL and LR |
Faces | 0° Aries - 30° Pisces, Zodiacal divisions, equal or unequal | Not numbered | Inner Circular, concentric | half circle inside the VI 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 | 0 - 12, Fingers | Every 1 fingers | Box | Right hand bottom face of the shadow square (in LR) |
Shadow square | 0 - 12, Fingers | Every 1 fingers | Box | Right hand vertical face of the shadow square (in LR) |
Transcription | Translation | Notes | Type |
---|---|---|---|
نقشه محمد مهدي اليزدي | Engraved by Muḥammad Mahdī al-Yazdī | Inscription in unusually-shaped cartouche. The inscription is worn and difficult to read | Maker's signature |