Portable Equinoctial Dial, 1900

Details

Description

This is an instrument that consists of a brass base and a brass stand on which a semi-circular metal dial … Read more This is an instrument that consists of a brass base and a brass stand on which a semi-circular metal dial plate and gnomon are attached. The base is circular and has a felt bottom. It has a compass set into it with a central needle, engraved cardinal directions and scale around the rim graduated in degrees. Next to this, on the vertical edge of the base, there is a small rod emerging from a slot. Sliding this fixes the compass needle in place. The top portion of the instrument consists of two semi-circular pieces. One of these is oriented vertically in order to hold a thin rod (the gnomon) in place, and the other horizontal half-moon piece is oriented more horizontally and is the dial plate set parallel to the Equator. The dial plate and gnomon portion of the instrument is controlled by a knob affixed to the stand of the instrument, which is attached to a broad needle that indicates on an arc shaped scale graduated from 0 to 90. The dial plate also contains an engraved scale. The number 12 appears in the middle of the intersection of the vertical and horizontal half moons while the left portion of the dial plate contains the numbers 1-8 and the right contains the numbers 11-4. These numbers represent the hours in a day. Size of the sundial:20 cm hughx8 cm diameter manufactured in USA See less