This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or “light”) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2×, and the afocal attachment may allow magnification of a received image at levels ranging from 2× to 4×. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4× to 8×. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4× magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.