The Celestron Universal Barlow & T-Adapter is three accessories in one! Use this telescope accessory as a 2X Barlow for visual use, as a prime focus T-adapter, or as a "Barlowed" T-adapter for double the magnification.
2X Barlow: Insert any 1.25" eyepiece into the chamber and you'll enjoy double the magnification, while retaining all the eye relief of the inserted eyepiece.
Prime Focus Photography: Use the T-Adapter portion of this accessory to transform your telescope into a giant telephoto lens. Just unscrew the bottom section of the unit to remove the Barlow and slide the chrome barrel into the telescope's 1.25" focuser or adapter. Lock it firmly in place with the focuser or adapter thumbscrew. The T-threads on the top of the adapter screw into a T-Ring (sold separately) that is designed to attach to the brand-specific mounting flange of your DSLR or SLR camera.
Tele-Extended Photography: Use the T-Adapter with Barlow to get double the magnification of prime focus mode. In "Tele-Extended" mode, the Barlow doubles the focal length and f/ratio of your telescope, resulting in an image on the sensor or film plane that is twice the size of a prime focus image.
Prime focus and tele-extended photography are popular for short exposure images of terrestrial objects as well as celestial objects like the Moon. A great 1.25" telescope accessory that allows you to have some flexibility in your astrophotography set-up. The T-threads accept camera brand specific T-Ring (sold separately).