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Quadrant (front)

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made in England

Quadrant (front)
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A quadrant is a quarter of a circumference of a circle. This brass example was used with a plumb line and bead for taking altitude observations. It was made in England in the early 17th century and is unsigned. The picture shows the front of the quarant.

The quadrant is laid out with scales that allow observations of the altitude of the sun (or particular stars) to be used to determine the time on a known date. There is a table of 11 named stars, marked on the projection below with corresponding numbers.

A development of the astrolabe and William Oughtred's horizontal instrument, this form of quadrant was described by Edward Gunter is his 1623 treatise, The Description and Use of the Sector, Cross-staff and other Instruments.

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