Augustus' sundial

Micro controllers
Vector graphics

My java applets were developed a long time ago and have not been digitally signed. Nowadays a browser will typically not allow a java applet to run unless it is signed. Getting the applets signed is somewhat expensive, and since I no longer do any java development it is unlikely that I will get the applets signed. It it still possible to run the applets, but in that case you will need to change the security policy of your browser to allow unsigned applets to run.
Augustus' sundial was the largest sundial of the ancient era. This sundial uses a large obelisk by whose shadow it is possible to tell the time of year and time of day. The first java applet below shows where the shadow of the obelisk falls during various times and parts of the year.

The hour lines of the sun dial do not quite show what we now mean by hours. Instead the hour lines divide the time between sun rise and sun set into 12 equal parts. This means that one "hour" during summer is longer than one "hour" during winter.

More about Solarium Augusti on wikipedia.

Below is a second variant of the applet. In this case where the shadow would fall right now is shown instead.

These applets were originally made (java code by Joakim Linde and graphics by Susanne Fagerlund) for the web site Tidsdokumentet (the time document), but since that site has not been online for quite some time the applets can go online again here.