Guildford Astronomical Society

Astronomy Applets and Applications

This page gives links to useful astronomical applications and applets that are available within the public domain.
Some apps will load directly and others will require downloading and installing before they can be run.

The page is currently under development, just one applet and one application are listed at present but others will follow.

Eclipsing Binary Simulator – The University of Nebraska-Lincoln

Can also be used to simulate exoplanet transits.
This simulator (click here to load) is part of the Eclipsing Binary Module of the Nebraska Astronomy Applet Project. Supporting materials and additional astronomy education resources can be found at
Funding for this work was provided by NSF grants #0231270 and/or #0404988.  Permission is granted to use this file for noncommercial purposes as long as it remains unmodified.


The Project site has a number of interesting astronomical educational and demonstration videos that can be found at

Will require Adobe Flash Player to be installed.

AstroClockFX by Joseph J. Novak

This very useful astronomy clock displays the current local & UTC date & time, a calendar, local & Greenwich sidereal times, and the Julian day. The menu items also include current data for the sun, moon, planets, eclipses, and other Solar System information plus event timers.  The algorithms used are based on Jean Meeus book “Astronomical Algorithms”.  Planetary images are generated by the JParsec Astronomical Library by T. Alonso Albi – OAN (Spain).


The clock can be downloaded where installation details are also given.
Will require Java8 – read the ReadMeFirst.txt file when the zip file is unzipped.