Please be patient while the applet loads into your browser. Once it loads, this applet will display a system of binary stars orbiting one another. Select a system from the menu labelled "Binary Systems", and the simulation will begin. You'll see a white window with one red dot and one blue dot. Clicking within this window will display the coordinates in Astronomical Units (AU). In the window labelled "Position and Time Data", the elapsed time (in years) and positions (x and y in AU) for stars A and B are constantly updating. Please click on the icon (looks like an x or a /) in the upper right corner of the "stars" window before selecting a second system -- only one should be running at a time.