You will first see a choice of three options: Optics, Rays, Media. You must select each one of these in turn by pressing the first letter, that is O, R, or M. In each case you will then see the new choices Dir, Edit, Fetchfile, Save, Clear. This are self-explanatory. Until you are adept at running the program, you should Fetchfile to recall a file we have written for you. Should you want to Save your work, give it a unique name. Please do not save files with the names we have in use.
Once you have ``fetched'' a file, the program will show you its contents. Each type of file - optics, rays or media - has a special way of listing its contents. Good examples to start with are in the files for chromatic aberration described below. You may see a list of available files by using the Dir command. You may edit a screen with the Edit command. This does not change the contents of the file on disk, just in the program's memory.
The optics, rays and media files are distinguished by their extension. For example, for chromatic aberration the files are PCCOLOR.OPT, PCCOLOR.RAY, and GLASS.MED. In some instances you won't need a media file, since it contains indices of refraction and dispersions. If your problem only uses mirrors in air, you will not need to load the media.
After you have fetched all three files, the main menu will include some new entries. It will read Optics, Rays, Media, InOut, Vx, Layout, Plot, Auto. If you still need to load an additional file, the main menu will be shorter, and the program will tell you what you need to do. Briefly, here are the functions of the new entries in the menu -