Astronomical Images : Measuring eclipses

Daniel Santbech

Astronomical Images

<p style='text-align: justify;'>Daniel Santbech's <i>Problemata</i> is a miscellaneous work in mixed mathematics, including astronomy, gnomonics, perspective, surveying, gunnery and navigation. The unifying element in such a wide range of disciplines is the instrument called the geometric quadrant. According to Lynn Thorndike, Santbech showed appreciation both for specific aspects of Copernicus's work, such as lunar theory, and for the <i>Prutenic Tables</i>, but he ignored cosmological issues. Copernicus is mentioned many times. Virtually nothing is known about Santbech, apart from the fact that he published, in addition to this work, an edition of Regiomontanus's <i>De triangulis</i> (Basel, 1561). The title-page calls Santbech '<i>Noviomagus</i>', and this is generally interpreted as meaning 'of Nijmegen', but Andreas Kleinert reports that Santbech could be from Speyer of Neumagen, a small town near Trier. The volume included a dedicatory letter by Santbech to '<i>Domino Joanni Ludovico a Windeck</i>', dated 1561. The existence of a 1542 Basel edition is disputed by Ernst Zinner. The figures in this edition seem to have been copied from Oronce Fine's <i>Protomathesis</i>. Here Santbech shows how to measure the magnitude of an eclipse, using divisions into twelve parts, each of which is divided into twleve parts again. In explaining this figure, Santbech refers readers to the eclipse observed by Gemma Frisius from Louvain in 1545, thus giving a real-life example as the basis for his textbook pronouncements.</p>