The Uni-Blug is used together with a regular single beam laser collimator to adjust the angular alignment of the primary mirror of a Newtonian telescope.
The Uni-Blug is the newest Newtonian collimation accessory (Blug is short for 'Barlowed Collimation Plug'). The Blug is used together with a regular laser collimator in single beam mode to perform Barlowed laser Newtonian primary mirror alignment. The Blug does not attach to the collimator like my regular self-Barlow attachment. It is inserted in the inner end of the focuser drawtube, inside the tube or upper cage, and it is retained by an O-ring in the Blug base. It has a matte-white 45 degree face as a screen, and a small anti-reflection coated Barlow lens mounted in a central axial hole.
