Beschreibung:

A brass quadrant, nocturnal, and Regiment of the Pole Star, probably English, late 16th-Century. The quadrant One side is marked with a small shadow square and below this an horological quadrant. Both are used with a pair of pin-hole sights; the hole for the plumb-line is at the apex, but there is no line present. The shadow square is divided along each edge in units to 6 at the 45 position. The arc of the quadrant is divided in single degrees which are labelled in tens to 90. Immediately above the degree scale is the solar altitude scale divided into five-day intervals from 10 December to 10 June, hat is from the Winter Solstice to the Summer Solstice. These dates mean that the Julian, or Old Style, calendar was being used. The placing of this altitude scale lies between 14 and 61, which means the quadrant is for use at the latitude 52. The hour lines have become faint through polishing, done most likely during the past century. The lines give the equal hours from 4 to 12 noon, and then to 8 in the evening; their form is that of Stffler (1561). Just visible is the wide curve of the ecliptic line that is marked at either end and in two places along its length with the symbols of the Zodiac. The nocturnal and Regiment of the Pole Star The outer edge is divided into the twelve signs of the Zodiac, each with 30 numbered in tens, labelled with the names and the symbols. There follows the calendar, in units of one day numbered in tens (or to 28 and 31), with names in English. The third band provides the age of the Moon, 0-29 days beginning and ending at the handle. This position is also marked in 12s, meaning the Moon is due south at 12 o'clock. At each following day there is an increment of 48 minutes in the time the Moon is south. The phase of the Moon is simulated by the aperture in the volvelle that rotates about the centre of the disc. The volvelle has two indexes, the longer is engraved with a hand, and points to the position of the Sun in the Zodiac. On the opposite side an index points to the age of the Moon. The edge of the volvelle is marked out in twice twelve hours. The central part is engraved with eight points of the compass and a band of degrees in four sequences from 0 to 4 9'. Across the band is a set of parallel lines connecting like numbers. It is this part that gives the measure of difference between the altitude of the true North Pole from the altitude, as measured, of Polaris (UMi). An adjustment is necessary because Polaris appears to rotate about the true Pole, so when it is North or South of the Pole, about 4 has to be subtracted or added to the altitude as measured by a quadrant, and when East or West no correction need be made to the value obtained for the altitude. Originally a curved arm would have been attached to a boss at the centre. This arm, known as 'the Horn', represented the constellation of Ursa Minor, with Polaris at one end and the 'guard' Kochab (UMi) at the other. It is possible to see where this curved arm was originally attached. The star Kochab also serves as an indicator when the instrument is used as a nocturnal. When the handle is held vertically, the meridian line passes through 9 Scorpio (22 October), which is correct for the period -- 56in. (13.2cm.) diameter See Colour Illustration and Details