you can use this handy scope as a deluxe, straight-through 50mm finder by inserting an optional 1.25" eyepiece (sold separately). A practical benefit of this is that prior to guiding, you can insert an eyepiece into the guide scope and easily align the guide scope with your main imaging telescope. Then remove the eyepiece and attach your autoguider camera NOTE: The fixed-orientation focuser mechanism will not rotate inserted autoguider cameras or eyepieces when focus adjustments are made. 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 Features: Versatile 50mm aperture Guide Scope with a built-in helical focuser for precise focusing of potential guide stars Designed for use with the guider CCD astronomy camera or eyepiece Helical focuser collar will not rotate attached autoguider devices during focus adjustments Used as a deluxe straight-through finder scope with optional 1.25" eyepieces installed (eyepieces sold separately) Specification: Type of Telescope: Achromatic Refractor Lens: Cemented Tube material: Aluminum Alloy Aperture: 50mm / 1.97in Focal Length: 190mm / 7.48in Focal Ratio: F4 Coating: Fully multi-coated Best for imaging: Deep sky User level: Intermediate Rough Focusing Range: 30mm Focuser: Helical Focuser with 8 mm Travel Connection to eyepiece: 1.25inch Tube diameter: 54.5mm Dewcap diameter: 61mm Total Length: 240mm Included accessories: Tube Rings and Dovetail Rail Package Includes: 50mm Primary Mirror Guiding Bracket w/ 89mm Dovetail Plate 1.25inch Helical Focuser 6PCS Metal Thumbscrews The SV224 dovetail base is suitable for most kind of telescopes and has strong compatibility. Drilled (but not threaded) to accommodate screws up to 5mm in diameter. Two thumbscrews are included in package which are fit into the recessed slotted mounting holes. Precision mac