Accession No

0608

Brief Description

universal equinoctial ring dial by Thomas Tuttell, English, c. 1700

Origin

Charing Cross; London; England

Maker

Tuttell. Thomas

Class

dials

Earliest Date

1695

Latest Date

1702

Inscription Date

Material

metal (brass)

Dimensions

length 210mm; diameter 150mm

Special Collection

Robert Whipple collection

Provenance

Purchased in 05/1930.

Inscription

‘Tho: Tuttell Charing + Fecit’ (meridian ring)

Description Notes

Universal equinoctial ring dial by Thomas Tuttell, English, c. 1700.

Meridian ring calibrated for all latitudes, divided in opposite quadrants 0 - [90˚], numbered by 10˚, subdivided to 30´. Suspension shackle with brass suspension ring. Equinoctial ring divided I - XII, I - XII, numbered by I, subdivided to 5 minutes. Pierced bridge with date scale divided to named (initialled) month, subdivided to one day (two days?; 17-1-2000); reverse carries declination scale divided 23˚ 30´ - 0 - 23˚ 30´, numbered by 10˚, subdivided to 30´ (1st Aries = 10 March); pinhole gnomon.
Reverse of meridian ring marked with altitude quadrant, divided 0 - 90˚, numbered by 10˚, subdivided to 30´.
Decorated bridge pivot supports hour ring stops.

Condition: good(/fair).

catalogue card - dials (universal equinoctial ring dials)

References

Events

Description
The universal equinoctial ring dial was designed by the English mathematician William Oughtred in the first half of the seventeenth century. It could be used at any latitude, so was a popular timekeeper for sailors and other travellers. It was really a much simplified version of the armillary sphere, only keeping the parts which were needed for telling the time.

The universal equinoctial ring dial consists of two rings and a bridging bar inside the inner ring. The outer ring represents a circle passing through the North and South celestial poles. The inner ring is called the ‘equinoctial’ ring because it represents the celestial equator. The bridging bar represents the axis of the world, just as the gnomon on an ordinary horizontal dial does. So the instrument is a very simple model of the heavens.

01/02/2001
Created by: Dr Hester Higton on 01/02/2001

FM:39999