Imperial square quadrant

[Imperial Square Quadrant]

The Imperial Square Quadrant was made at the Palace Building Office of the Qing Dynasty during the reign of Kangxi in the Qing Dynasty, with a side length of 32 cm. The old collection of the Qing Palace
This instrument was made by the Qing Palace Building Office in imitation of the Western quadrant. The instrument panel is made of copper and is square. The scales on the two straight sides of the panel intersect with horizontal and vertical lines to form a tenfold grid, and is engraved with 0 ° – 100 °. The surface of the secondary internal quadrant is intersected by arcs and oblique lines into a tenfold grid, and is engraved with 0 ° – 90 °. A square plate is set adjacent to the quadrant surface, and the center of the plate is embedded with a compass. The instrument panel is decorated with hollowed-out grass patterns. The collimator is set at both ends of the panel along the side for calibration. A vernier with a peephole is set next to the collimator. The instrument panel is supported by a three-leg bracket inlaid with copper on a mahogany column. The bracket is partially spiral and can be adjusted to lift the instrument for horizontal or vertical measurement
Square quadrant is one of the early quadrants in Europe. It is used to measure the horizontal angle, the height of a celestial body from the horizon and the distance from the zenith. If measuring the horizontal angle, that is, set the north-south direction by the compass, straighten the plumb line, aim at the observation target A through the collimator, then aim the vernier peephole at the observation target B, and look at the scale indicated by the vernier on the dial, that is, the horizontal angle to be measured
The inscription “Emperor Kangxi” is engraved on one corner of the instrument