Example image of eyePlorer eyePlorer map for 'Willebrord Snellius': Snellius (crater) 1626 Astronomy Leiden Mathematics Netherlands October 30 Ibn Sahl Rudolph Snellius Latitude Triangulation Alkmaar Bergen op Zoom Eratosthenes Kilometre Snell's law William IV, Landgrave of Hesse-Kassel Trigonometry List of craters on the Moon Timeline of electromagnetism and classical optics Jean Picard 1626 in science Snellius–Pothenot problem Michael van Langren Willem Blaeu List of mathematicians (S) Scientific phenomena named after people List of astronomers Bernhard Walther Edward Wright (mathematician) List of Dutch people 1580 1621 Resection (orientation) List of physicists Christoph Rothmann Snell Snellius Apollonius of Perga Thomas Harriot Area of a disk Simon Stevin Theodolite 1620s Ramism Richard Norwood History of optics List of eponymous laws List of villains in Totally Spies! Franciscus Vieta