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Horizontal, Equatorial, and Vertical Sundial

 Albrecht Dürer (1471-1528), the famous Renaissance painter, printmaker, engraver, mathematician, and theorist, presented a drawing with a detailed method for the construction of sundials using compass and straightedge. He published it in 1525 in the third book of his treatise >Underweysung der messung, mit zirckel und richtscheyt< (Teaching of Measuring).

 Enter latitude in decimal degrees, and press RETURN key. Enter longitude in decimal degrees (eastern positive, western negative) and press RETURN key. Use Shift key and click to move the center.

 Setting the longitude to zero the hour lines will indicate the local apparent time (solar time). Taking into account the longitude the hour lines will indicate the standard time if the equation of time is added or subtracted. + = sundial is fast on clock time - = sundial is slow on clock time

The sundial is using a polar gnomon (parallel to the Earth's axis).

Testing the sundial at 51.62° N, 7.97° E on May 12 at 14:05 CET
(equation of time 3:40 min, dial is fast)

 Web Links Albrecht Dürer: Underweysung der Messung, mit dem Zirckel und Richtscheyt (Sächsische Landesbibliothek -Staats- und Universitätsbibliothek Dresden) Underweysung der Messung, mit dem Zirckel und Richtscheyt, in Linien, Ebenen unnd gantzen corporen/Drittes Buch (Wikisource) Books Albrecht Dürer: Unterweisung der Messung mit dem Zirkel und Richtscheit, Faksimile-Neudruck der Ausgabe Nürnberg 1525, Verlag Dr. Alfons Uhl, Nördlingen 2000, ISBN 978 3 921503 17 1.

Updated: 2023, Oct 06