Francisci Sarzosi aragonei, in aequatorem planetarum libri duo. Prior fabricam aequatoris complectitur. Posterior usum atque utilitatem, hoc est veros motus ac passiones in zodiaci decursu contingentes, aequatoris ministerio investigare docet
Paris: Apud Simonem Colinaeum, 1526.
Price: $16,500.00
Folio: 31 x 21.5 cm. 41, [1] lvs. Collation: A-G6
FIRST EDITION. The earliest reference to Zarzoso’s book comes from the 17th c. Jesuit astronomer Riccioli, who mentioned an -untraced- edition of 1525. The consensus is that the 1526 is the first edition.
Bound in modern brown calf, ruled and tooled in blind (some mild surface wear.). A fine copy internally, with the oversize illustrations on leaves 14, 16, 18 and 19 folded in to avoid trimming. Light soiling to title page, blank upper corner of leaf 2 restored without loss. Small ink smudge on leaf D1, ink marks to lower margin of the following leaf, some insignificant marginal blemishes. Illustrated throughout with diagrams and the components of Zarzoso’s instrument. Provenance: two Handwritten inscriptions on the title page: Congrégation des Bénédictins de Saint-Maur and abbaye de Saint-Germain-des-Prés (with the armorial stamp of the latter).
First edition of this work by the Spanish astronomer and instrument maker Francisco Martínez Zarzoso (whose name is variously rendered Zarazoso, Zarzosa, and Sarzosa) detailing the construction and use of his advanced equatorium, a mechanical instrument for calculating planetary motions. Although planetary equatoria had existed since the 11th century, Zarzosa introduced a number of advances that increased the instrument’s precision and made it easier to use. The example preserved in the Billmeir Collection at the Oxford Museum of the History of Science can be attributed with confidence to Zarzoso.
Zarzoso was educated at the University of Paris, where he studied theology, mathematics, and astronomy. It was while in Paris that he created his instrument and wrote his book, in which he explicitly used the Paris meridian as the basis for its astronomical calculations. Upon his return to Spain in 1530 to take up his appointment as vicar of the town, Zarzoso established an observatory in his home.
The book was published at Paris by Simon Colines and is a fine example of French printing. The title page border of decorative knotwork on a criblé ground, with small figures representing Astronomy, Music, Orpheus, Geometry, Euclid, Arithmetic, and the astronomers Ptolemy and Al-Khwârizmî, is attributed to the polymath Oronce Finé, who, like Zarzoso, also designed instruments for making astronomical and terrestrial measurements. The elegant type and decorative criblé initials are attributed to Geoffroy Tory.
Zarzoso’s book is divided into two main sections. The first part focuses on the construction of the equatorium, providing detailed, step-by-step instructions for assembling the device. The second part is dedicated to the practical use of the instrument, explaining to readers how to calculate true planetary movements, zodiacal positions, and eclipses. The book is outfitted with a set of accurate tables, calculated for the years 1520 to 1600, that were later praised by Tycho Brahe, who referred to them while making his planetary observations.
Inspired by a well-constructed astrolabe, Zarzoso envisioned an equatorium that could be used by navigators and astronomers, as well as by his own students. While an astrolabe projects the celestial sphere onto a plane to locate the sun’s position, Zarzoso's equatorium extended this capability to the planets.
The equatorium simplifies planetary movements by breaking them into constant and variable elements. Constant elements include distances and radii, while variable elements depend on the date and include true and mean motions, centers, and arguments. Zarzoso’s design represents these variables in a circular, planar format, avoiding the complexities of eccentric orbits.
While each planet typically requires its own epicycle, Zarzoso reduced the number to three: one for Mars, Jupiter, and Saturn; another for Venus and Mercury; and a separate one for the Moon. This new design minimized complexity while maintaining precision.
For a more detailed description of the book and the instrument, see Angel Aguirre Alvarez’ article, “El Astronomo Francisco M. Zarzoso, Datos biograficos y studio de su obra”, Llull, Vol 2, December 1979, 23–42.
Mortimer (French) 482. Houzeau-Lancaster 4782. Thorndike V, p. 284. Cantamessa III, 7102. Palau 302699. Renouard, Bibl. des editions de Simon de Colines, p. 91. Picatoste y Rodriguez, Biblioteca cientifica espanola del siglo XVI, 752. John North, Cosmos: An Illustrated History of Astronomy and Cosmology, 2008. Further reading E. Poulle et F. Maddison, “Un équatoire de Franciscus Sarzosius”, Physis, t. 5, 1963, p. 62, n. 1 (not consulted.)