The Apparent Motion of the Sun at Different Latitudes

Applet

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If you can't run this applet properly, please download the latest version of the Java Runtime Environment (JRE) at < a href="http://java.sun.com/j2se/">http://java.sun.com/j2se/.

This applet was made together with Tey Meng Khoon and Frederick H. Willeboordse of CITA (Centre for Information Technology and Applications) for the course Heavenly Mathematics & Cultural Astronomy.

Video Clip

I have recorded a video clip that explains this applet. It's available in several formats.

If you can't get any sound in the QuickTime file, you may need to download the latest version of QuickTime.

Discussion

This Java applet shows the motion of the Sun as seen from the Earth. You can select your geographical position, and you will see how this changes the Sun's path across the sky. The observer is always on “top” of the sphere as indicated by the bright dot on the sphere. The place turns dark when the sun sets but is lighted when the sun rises. You can move the time slider or just let the animation continue to see the motion of the sun in the course of the year. You can slow down the animation to see the effect more clearly.


Helmer Aslaksen
Department of Mathematics
National University of Singapore
helmer.aslaksen@gmail.com