The back contains 4 scales of the following types:
| Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
|---|---|---|---|---|
| Zodiacal signs | 0 - 30, Zodiacal divisions, equal or unequal | Not numbered | Circular, concentric | The entire outer circle on the back of an astrolabe. |
| Calendar | first day of month - last day of month, Days of year | Not numbered days | Circular, eccentric | Circular scale immediately inside the outer scale - refers to the full circle |
| Shadow square | 1 - 12, Fingers | Not numbered fingers | Box | All four sides of the shadow square, commonly found in the lower half of the center of the instrument. |
| Solar cycle | None | Inner Circular, concentric | First circle within shadow square. |