The EJS Gnomon model simulates the shadow cast by a gnomon (the part of a sundial that casts the shadow) over the course of a day for any day of the year and any latitude on Earth. The program gives you the option to use mean Sun (which moves relative to the stars at a constant rate throughout the year) or true Sun (which varies its apparent speed relative to the background stars). The default is to use true Sun. The program also shows the observer's horizon plane on the spherical Earth, as well as the ecliptic and the apparent path of Sun. The Earth View can be set to let Earth rotate or remain fixed EJS Gnomon model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Gnomon.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.


  • Education > General

Education Levels:

  • Grade 1
  • Grade 6
  • Grade 8
  • Grade 9


NSDL,Sun,Undergraduate (Lower Division),oai:nsdl.org:2200/20090907192654169T,Space Science,shadow,Easy Java Simulations,OSP,Astronomy,Informal Education,Higher Education,Middle School,Historical Astronomy,gnomon,History/Policy/Law,Physics,General Public,Computing and Information,EJS,Education,History of Astronomy,High School,NSDL_SetSpec_439869,Vocational/Professional Development Education,Earth,Astronomy Education,Geoscience,Open Source Physics



Access Privileges:

Public - Available to anyone

License Deed:

Creative Commons Attribution Non-Commercial Share Alike


This resource has not yet been aligned.
Curriki Rating
'NR' - This resource has not been rated
'NR' - This resource has not been rated

This resource has not yet been reviewed.

Not Rated Yet.

Non-profit Tax ID # 203478467