Versatile 60mm aperture Guide Scope with a built-in helical focuser for precise focusing of potential guide stars; will help guide you to capturing higher quality astrophotos;an ideal addition to any astrophotographers collection of gear | The helical focuser simply moves the attached device inwards or outwards while maintaining its orientation;this convenient feature means your field of potential guide stars will not rotate as focus is adjusted, further increasing ease of use | For those nights when you don't plan to capture astrophotos exposures, this versatile Guide Scope can double as a straight-through finder scope with an optional 1.25" eyepiece installed;For example, inserting a 25 mm eyepiece creates a 9.6x60 finder scope, or you can insert one Illuminated Centering Eyepieces for use as a finder with illuminated crosshairs for easy aiming | The focuser boasts 8 mm of precise helical focus travel;plus telescoping drawtube housing provides up to 35mm of additional back-travel if needed for your particular autoguider device;No extension tubes necessary; a compression ring fitting keeps any inserted autoguider cameras or eyepieces free of pesky scratches | The Multi-Use Guide Scope with Helical Focuser also features male T-threads on the focuser collar for secure threaded attachment of guide cameras equipped with female T-threads