Gnonom shadow at noon on the Vernal/Autumnal Equinox.
Gnonom shadow at noon on the Vernal/Autumnal Equinox.
The Noon Shadow model shows the geometry of the shadow (magenta) cast by a gnomon (green) at noon. Users can change the orientation of the gnomon as well as the gnomon's latitude and the day of the year. The height of the gnomon and its shadow length are displayed in Earth radius units.
The Noon Shadow model was created by Wolfgang Christian and Todd Timberlake using the Easy Java Simulations (EJS) version 4.2 authoring and modeling tool.
You can examine and modify a compiled EJS model if you run the model (double click on the model's jar file), right-click within a plot, and select "Open EJS Model" from the pop-up menu. You must, of course, have EJS installed on your computer. Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.