Alidade

An alidade is a sighting device that is used to measure angles.

The earliest alidades were simply long sticks with sighting slots. They enabled early astronomers to measure the relative angles between stars and thus to produce the earliest star maps.

Over the years they became more and more sophisticated and incorporated small telescopes, for example, as used in the modern theodolite by terrestrial surveyors.

Comments are closed.

Switch to our mobile site