The Celestron Off-Axis Guider is an essential astroimaging accessory for long focal length telescopes providing the most accurate guiding possible. It uses a prism to intercept a portion of the telescope s focal plane allowing the guide star to be tracked and any movement to be corrected resulting in better astroimages with pinpoint round stars. The Off-Axis Guider addresses common challenges by offering a large adjustable prism for brighter guide stars a high-quality Helical focuser for smooth and accurate focus and all the necessary adapters for a variety of imaging configurations including DSLR and CCD cameras.