The back contains 5 scales of the following types:
| Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
|---|---|---|---|---|
| Degree | 0 - 90, Degrees | Every 10 degrees | Circular, concentric | Upper right quadrant of outer circular on back of instrument. |
| Degree | 0 - 90, Degrees | Every 10 degrees | Circular, concentric | Upper left quadrant of outer circular on back of instrument. |
| Zodiacal signs | 0 - 30, Zodiacal divisions, equal or unequal | Every 10 | Circular, concentric | Circular scale immediately inside the outer scale - refers to the full circle |
| Calendar | First day of the month - Last day of the month, Days of year | Every 10 and end of month days | Circular, eccentric | Circular scale second in from the outer scale - refers to the full circle. |
| Shadow square | 1 - 12, Fingers | Every 3 fingers | Box | Left hand vertical 'face' of the shadow square (in LL) |
| Shadow square | 1 - 12, Fingers | Every 3 fingers | Box | Right hand vertical face of the shadow square (in LR) |
| Shadow square | 1 - 12, Fingers | Every 3 fingers | Box | Left hand bottom face of the shadow square (in LL) |
| Shadow square | 1 - 12, Fingers | Every 3 fingers | Box | Right hand bottom face of the shadow square (in LR) |