| This alignment is performed with the aid of an alidade, or sight rule, a straightedge fitted with simple sights. |
| At choice two different sighting telescopes with vertical circle are available: The autoreduction telescope of the MEDIA and the standard telescope of the MEJUN alidade. |
| An optical plummet, built into either the tribrach or alidade of total station instruments, permits accurate centering over a point. |
| Close by stood an alidade, an instrument for measuring angles. |
| After he had placed the plane table on a tripod and upon this the alidade, he started to work. |
| With the aid of a double alidade with sights, it was possible to measure angles whose accuracy, however, did not exceed? |
