Schematic drawing of our optical diffractometer, which is mounted on a horizontal table. The film mask can be either rectangular or circular and can slide along the optical axis, which changes its effective size on the film. The 60mm lens is removable and, when inserted, allows an image to be viewed. The diffraction pattern (or image) is viewed on the TV (via the B/W CCD camera) and the video graphic printer provides an instant copy of this image. Alternatively, a frame grabber (Data Translations 3152) in a personal computer is used to capture the image using ImageTool software for a digital record.