7. Ecliptical astronomical ring
XVI-XVII cen. ?
author unknown
brass
diameter 23.5 cm
[Inv. MdS-12]

Astronomical ring to measure ecliptical latitudes and longitudes, consisting of seven rings - armillae - the biggest of which is c.23 cm in diameter. A smaller ring, sliding on the latter, measures local latitude. The fourth and fifth rings, which represent the zodiac and a circle perpendicular to it, revolve on the smaller ring, around the celestial pole and carry, pinned to the pole of the ecliptic, the third and sixth rings. Inside this latter, finally, is the seventh with the two sighting vanes for focusing on a celestial object. The first, third, fifth and sixth rings are graduated.
The inclination of the ecliptic is about 23.5 degrees.
Decidedly unrefined, the workmanship points to an essentially didactic use of the instrument.
Descriptions of this type of instrument and its use can be found in the XVIth-century work of Johann Werner (1468-1528) and Apianus (Peter Bienewitz) (1495-1552).

P. Apian (1539).
J.A. Bennett (1987), p.21.
A.J. Turner ed. (1990), p.121.
G.LE. Turner (1991), p.124 ff.
J. Werner (1533).