This eyepiece socket fits the thread of the Schmidt-Cassegrain
telescopes and allows the use of 1.25-inch accessories – for
Example of a straight view with 1.25″ eyepieces, for star diagonals and
similar.
This adapter is part of the standard scope of delivery for all Celestron 5″,
6″, 8″, 9.25″ and 11″ Schmidt-Cassegrains.