A rare heliostat signed on the white enamel dial
A. Prazmowski. 1, Rue Bonaparte, Paris.
The dial is graduated around three-quarters of the circumference IV-XII and I-VIII with ten-minute subdivisions, subsidiary seconds dial. The heliostat is placed between two tapering brass uprights, one of which has a pierced vertical quadrant, ungratuated, mounted on the inside, with screw clamp. Placed on a brass circular brass plate with a pierced centre. The brass drum houses the mechanism, with a winding key at the back. The octagonal mirror is mounted in the centre on threaded split sleeve with a knurled tightening wheel.
A heliostat is an instrument designed to capture a reflection of the Sun (or other Celestial body) over a period of time, by rotating a clockwork mirror to match the Sun’s apparent path through the sky.
Diameter 9,6 cm.
France, circa 1880.
In good condition.