The back contains 2 scales of the following types:
| Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
|---|---|---|---|---|
| Degree | 0 - 360, Degrees of arc | Every 6 in upper left quadrant. degrees | Circular, concentric | The entire outer circle on the back of an astrolabe. |
| Sine/Cosine | 1/60 of quadrant radius | Not numbered | Angle | Upper left quadrant (inside circular scales) |