Abstract: Telescopes have many accessories including astrophotography devices. A finely threaded accessory ring of conventional diameter is provided on these telescopes with the accessories being screwed thereinto with the constant danger of cross-threading. The present invention is threaded into the accessory ring of the telescope and on to the mating threads of the accessories. Through the use of the adapter of the present invention, the male adapter includes an outwardly projecting locking pin and the female adapter includes a mating, generally L-shaped locking slot to allow slide-on and twist locking and twist and slide-off unlocking. This can be accomplished in one to two seconds versus ten to twelve seconds to install and seven to eight seconds to remove accessories using the conventional thread-on, thread-off method.