Accession No

1204

Brief Description

horary quadrant, unfinished, English, second half 17th Century

Origin

England

Maker

Class

dials

Earliest Date

1650

Latest Date

1700

Inscription Date

Material

metal (brass)

Dimensions

breadth 220mm; length 230mm; thickness 9mm

Special Collection

Provenance

Transferred from the Museum of Archaeology and Ethnography, University of Cambridge (now Museum of Archaeology and Anthropology).

Inscription

Description Notes

Square brass plate.
Obverse: incomplete Gunter projection for 51˚ 30´ N with hour arcs divided 6 - 12, 1 - 8 and date scale divided to month and subdivided to 1 day.
Reverse: circle divided 0 - 90˚ - 0 - 90˚ - 0, numbered by 10˚, subdivided to 30´. 8 points of the compass lettered. Pierced to take a disc (not extant). Only one sight present. [The dial is only partially finished and the plate is unpolished.]

References

Events

Description
Quadrant
A quadrant is a quarter of a circle, and there are different types of instrument that come under that description. The size of quadrants varied hugely from Tycho Brahe’s highly successful huge 2m radius one, to the more portable versions of the 18th century. In all examples, it was important to keep movement, wear, and flexure to a minimum, especially if results were to form part of an extended research program and to be compared with one another.

The quadrant was the principle measuring instrument of astronomy in the 17th and 18th centuries, being used in all major observatories. Plain sights (where the angle was simply read off by eye) were replaced by telescopic sights in more sophisticated examples.

18/10/2002
Created by: Saffron Clackson on 18/10/2002

FM:43538