Skypoint 0.5X Reducer halves the focal length of your telescope, giving you a much wider field of view. You can use this, for example, for doing astrophotography using an astronomy webcam. Using the reducer is ingeniously simple - it is threaded for attaching to a 1.25" filter thread, which lets you easily screw it into any 1.25" eyepiece or 1.25" camera adapter. Screw the Astromania reducer into the filter thread on your camera and so double the size of the photographic image field. This lets you take images of much larger areas of the lunar surface, for example. The reducer is also great for taking videos of the Moon using your webcam. You can obtain even larger image fields with your astronomy webcam if you attach an extension tube (e.g. 25mm) between the reducer and camera.Screw the reducer into a 1.25" eyepiece and you have a smaller magnification and hence a significantly larger field of view. You can use the reducer if you don't have the correct eyepiece. The reducer is optimal for achieving a focal length of up to about 25mm.