The back contains 4 scales of the following types:
| Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
|---|---|---|---|---|
| Calendar | Days of year | Not numbered days | Arc | None |
| Unequal hours | 1 - 12, 1/12 of daylight | Every 1 hours | None | None |
| Equal hours | 1 - 12, 1/12 of daylight | Every 1 hours | Circular, concentric | second outermost scale on the front of the limb |
| Degree | 0 - 90, Degrees | Every 10 degrees | Circular, concentric | outermost scale on the front of the limb |