Alstar 2-Inch Telescope Eyepiece Extension Adapter, 50mm, Manual Focus, for Astrophotography

Alstar 2-Inch Telescope Eyepiece Extension Tube Adapter provide extra focuser back travel sometimes needed to achieve focus with certain eyepiece or telescope combinations. More back travel is often needed for short-range terrestrial viewing or with use of a field flattener, coma corrector, or focal reducer lens. Extension tube provides extra focuser "back travel" often needed for short-range terrestrial viewing through a telescope, or for astrophotographic applications. Extension tube provides extra focuser: back travel often needed for short range terrestrial viewing through a telescope; or for astrophotographic applications Features two locking thumbscrews to secure any inserted astronomy accessory; with a brass compression insh to prevent the marring of your telescope accessories Machined of high quality aluminum and anodized black; resistant for long time use Fits in 2 inch telescope focusers and accepts 2 inch eyepieces or accessories; Threaded for use with standand 2 inch astrophotography filters