alidade
- noun
- /ˈælɪdeɪd/
- Specialized
:
alidad
- The basic structure of the telescope consists of the rotating lower section, known as the alidade, and the tipping structure, which tilts within it.
Examples
-
While drawing the map, the cartographer adjusted thealidade to ensure precise direction readings.
-
According to Lewis, it appears that in most cases the horizontal reference was established using an instrument called a dioptra, which was a suspended vertical sector fitted with an alidade and leveled by fore and back sighting.
Academic text (2003) -
The company disassembled the alidade for shipment and later reassembled it in the cold of a West Virginia winter.
Academic text (2004) -
The distance between the two towers of the alidade that support the tipping structure decreased by an inch and a half from initial measurements because of thermal contraction.
Academic text (2004) -
The surveyor used aalidade to accurately measure the angles needed for the land mapping project.
-
Using analidade with the plane table, she marked the locations of significant landmarks on her map.
Synonyms
A straight edge with sights used on a plane table, a flat table for drawing maps
How Accurate
- Specialized
205
2.6
- Specialized
- Specialized
1
9.9
- Specialized
62
1.6
Surface Forms
Etymology
Alidade comes from old Spanish and Portuguese forms that include the Arabic article al- meaning 'the' and a root meaning 'rule' or 'measure', so it originally named a 'measuring rule'. That's why an alidade is the sighting part on a map or instrument used to measure directions and angles, like a ruler.