Astronomical Compendium with Rojas dial in polychrome ivory, brass, steel, glass and paper. This compendium includes an horizontal dial with a string-gnomon with compass, two equinoctial dials, a Rojas-dial and a Moon dial.
Oval shape with two ivory leaves (4 faces) hinged by copper wires with four silver hooks and a gripping ring.
Note : Juan de Rojas is a Spanish mathematician and astronomer of the XVIth century, he was a pupil of Gemma Frisius. He is the popularizer of “the orthographic projection” and applied it to the construction of astrolabes. It is a planar projection of the sphere which keeps the plane of the solstices' colure as projection plane.
Reference : a similar model, but simpler and without a lunar volvelle, dated circa 1573, is in the Galileo Museum in Florence, cat.50.
Dimensions : oval shape, length of 9,5 cm x width of 7,7 cm x thickness of 2,5 cm.
Paris circa 1590.
Reference : D/D ex Bo
Price and additional photos on request.
Also discover many more sundials in ivory in the dedicated section of our French website : « Cadrans solaires en ivoire ».
