Simplified light-weight sextant - has one-piece metal pressing incorporating arms, arc and mountings

摘要

The light-weight sextant uses a frame pressed from bar metal, the arms and arc of which have the same cross-sectional area, to produce a rigid component of long-term stability. The arms and the arc have the same width and have a cross-sectional area of not less than 2 sq. cms. The mounting for the eye-piece and the fixed mirror are attached to projections formed in the outer edges of the arms to provide extra strength. The light filters are mounted on the same position as their associated mirrors. The apex of the triangle formed by the two arms is somewhat enlarged to accommodate the bearing for the pivotted alidade arm and mirror.