This applet is part of the webpage [url=https://fransvanschooten.nl/sundialTulun.htm]https://fransvanschooten.nl/sundialTulun.htm[/url] and discusses a replica of an ancient sundial which is on display in the Istanbul Museum of Science and Technology in Islam.[br][br]The applet shows how to calculate the precise position and length of its shadow caster, the perpendicular style.[br]