Rule, Regula, Pointer and Alidade Images
Alidade Image:
 
    | Date | 18th century | 
| Place | India | 
| Material | Brass | 
| Inventory no. | 52478 | 
| Acquisition | Presented by J. A. Billmeir in 1957 | 
| Appearance | Tip | Sights | Pinholes | Notches | Description | 
|---|---|---|---|---|---|
| Double-ended, original. | Simple | Rigid | Single | None | A remarkable feature of this alidade is the sighting tube attached to the two sights. It has a large diameter and might have been used for sighting at night.. |