Alidades

Abstract

Alidade is used to measure angle of elevation and depression. It is a surveyor's instrument used by Civil Engineers, Mining Engineers. Generally simple type of Alidades are made of teak-wood, highly polished with brass hinged vanes and acquired, fitted with circular bubbles. Other design of alidades is a simple Telescopic alidades with angle measuring to minutes reading by vernier. Alidades of teakwood or brass plate with 'two 'folding sights are available in sizes 30 ems, .15 ems, 60 ems. Telescopic Alidades has a telescope equipment to focal length' internal focussing type, 19 em, magnification 13.5 with glass etched diapharm.