Dial of shepherd

A dial of shepherd is a Sundial portable making it possible to read l´heure on a vertical surface.

Operation

A dial of shepherd is made up d´un Cylindre d´une ten centimetres height on which appear of the time lines, variables according to the Saison S and the Latitude, and of a metal blade which can be placed with l interior of the cylinder. The cylinder can be out of wood or metal. The graduations often printed on a paper rolled up on the cylinder or are engraved directly on this one. For reading l´heure, it is enough to hold the dial vertically, to position the blade opposite the date and l´orienter towards the sun. L extremity of the shade of the blade then will be related to the time line corresponding to l´heure.

History

The dial of shepherd is very old in his principle: a model of old the Rome was found with Este close to Padoue (Italy) and goes back to the first century of our era. It was reinvented thereafter (for example by the monk Herrmann der Lahme (1013-1054)). It was then adopted by the Berger S of the the Pyrenees (from where its name) at the beginning of the 20th century. It was sold for 5 francs with Paris in 1849.

References and sources

Dial of Padoue: Newspaper for the History off Astronomy, Vol.28, Part.2, pp.107-117, 1997

Internal bonds

Herrmann der Lahme

External bonds

of dial of shepherd
explanatory Diagram

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