3-ring universal ring sundial
Date: circa 1780
Inventory Number: 7869
Classification: Sundial
Subject:
Maker: Etienne Lenoir (1744 - 1832)
Collector: David P. Wheatland (1898 - 1993)
Cultural Region:
Place of Origin:
Dimensions:
closed: 14.8 x 21 x 5.3 cm (5 13/16 x 8 1/4 x 2 1/16 in.)
DescriptionThis armillary ring dial is based on the astronomical ring of the 16th century, having three nested rings and an alidade.
The merididan ring is divided 90°-0°-90°-0°-90°, every 30'. It has steel supports to hold the internal ring. The shackle and suspension ring are very elegant with a gimballed ball joint and a double track for sliding around the meridian ring. There is a vernier scale on the slider where it meets the latitude scale on the meridan ring. The vernier is divided 30-0-30, and so can be set for latitudes to a minute of arc.
The equatorial ring is divided into hours I-XII twice, with subdivisions to 5 minutes. It can be used to in finding the hour or in finding the right ascension of a star or planet.
There is a four-spoked internal ring for setting or finding the solar declination. It can also be used for finding the declination of a star or planet within the range of its limits. It is divided from 45°-0°-45°, every 30', with a vernier giving readings to 1'. The vernier is at the end of an alidade which has 6 pinhole sights at each end. These can be used in spot-and-target fashion with sunlight using the pinholes at opposite ends.
The merididan ring is divided 90°-0°-90°-0°-90°, every 30'. It has steel supports to hold the internal ring. The shackle and suspension ring are very elegant with a gimballed ball joint and a double track for sliding around the meridian ring. There is a vernier scale on the slider where it meets the latitude scale on the meridan ring. The vernier is divided 30-0-30, and so can be set for latitudes to a minute of arc.
The equatorial ring is divided into hours I-XII twice, with subdivisions to 5 minutes. It can be used to in finding the hour or in finding the right ascension of a star or planet.
There is a four-spoked internal ring for setting or finding the solar declination. It can also be used for finding the declination of a star or planet within the range of its limits. It is divided from 45°-0°-45°, every 30', with a vernier giving readings to 1'. The vernier is at the end of an alidade which has 6 pinhole sights at each end. These can be used in spot-and-target fashion with sunlight using the pinholes at opposite ends.
In Collection(s)
Signedon spoke: Lenoir à Paris
FunctionThe armillary ring dial is based on the astronomical ring devised by Gemma Frisius in the 16th century. It is an instrument for precision time finding by the sun, and for making observations of the right ascension and declinations of stars and planets near the ecliptic.
ProvenanceDavid P. Wheatland, Topsfield, MA; gift to CHSI.