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TS Optics Non rotating helical focuser with M48 connection A true helical focuser like this works like a camera objective - when you turn the focusing ring, neither the lens nor the camera (or eyepiece and diagonal) will rotate. The only motion is in and out. The advantage of this helical focuser is the fine adjustment, possible in part due to the fine pitch of the focusing ring's thread, and in part due to the large diameter of the ring. In the case of this helical focuser, virtually backlash-free movement and graduated markings on the focusers allow repeatable return to the focus point simply by noting the focus position reading. Advantages at a glance no rotation of the diagonal or camera - the only motion is in and out precisely adjustable limitedly self-locking wide focus range: 40 mm 51 mm minimum height, 91 mm maximum height easy adaption to the telescope tube and the camera good solution for telescope or objective self construction M48x0.75 (2" filter) threads at both sides, with all adaption possibilities generous clear aperture of 45 mm also suitable as variable M48 extension 51 mm to 91 mm for the perfect working distance two screws for locking the drawtube Wide focussing range and short length The Helical focuser has a wide focussing range of 40 mm, but it is very short, with a minimum height of only 51 mm. So you can use the focuser on telescopes or telephoto lenses with little space to the focus point, like Newtonians. Accessories This focuser is not suitable for heavy accessories, it will tilt. The main use is with small CCD cameras for planetary photography, 1.25" eyepieces and lightweight 2" eyepieces. Delivery contents Helical Focuser with 2 locking screws

Item condition: new, but not original packed