Celestron Eyepiece socket 1¼

A visual back is a metal adapter that screws onto the standard rear cell threads of Schmidt-Cassegrain and Maksutov-Cassegrain telescopes and accepts 1.25-inch accessories, including diagonals, eyepieces (for straight-through viewing), Barlows, webcams, and any other accessory with a 1.25-inch insert barrel.

All Celestron 5-inch, 6-inch, 8-inch, 9.25-inch, and 11-inch Schmidt-Cassegrains come standard with the 1.25-inch visual back.

To use 2-inch diagonals on a Celestron 5-inch to 11-inch Schmidt-Cassegrain, remove the visual back and thread on a 2-inch diagonal made especially for Schmidt-Cassegrain telescopes, such as the Celestron 2-inch XLT diagonal.