This guide scope takes does the job of a "classic" guide scope - but it is lighter and much easier to use! Previously, long and unwieldy guide scopes were used to locate a guide star. But this is no longer necessary! The sensitivity of modern astronomy cameras makes this possible. You simply attach the mini guide scope onto your telescope like a finder.Or you can use it as a convenient, large finder scope and spend less time locating objects when visually observing. What is special about our Alstar guide scope? 1)It has a built-in worm-gear focuser with 10mm displacement, allowing very precise focus adjustment. The mechanism has a fixed orientation - so there is no rotation of mounted cameras or eyepieces - or also the field of view with your guide star - when focusing. 2)The robust metal housing is made of black, anodized aluminium: It not only looks solid, but is very sturdy. A milled and knurled focusing ring allows straightforward and precise fine focusing. It comes with matching tube clamps and a Synta-style mounting plate to make assembly and disassembly as simple as possible. 3)The 70mm Guide Scope is a complete and compact guide scope solution designed for use with nearly each autoguider and CCD camera in the market. 4)The included adapter plate can be used to attach the dovetail base and 70mm Guide Scope to any standard dovetail plate or side-by-side plate if preferred. If you need a Guide Scope Mount, We'd recommend the ASIN: B015VZGP52 - Alstar Guide Scope Mount - the convenient way to mount your guide scope. 5)Consisting of a 70mm aperture, 400mm focal length achromatic refractor guide scope, an adjustable dovetail guide scope bracket, an 1.25" aluminum parfocal ring, an adapter plate, the 70mm Guide Scope makes it easy for any astro-imager to enjoy the precision of autoguiding in their images.