Arcturus SCT Male to M45.4 MK Maksutov Female Adapter Ring For Astronomical Telescope

This adapter ring the convert the threads on the rear cell of many Maksutov-Cassegrain telescopes (including some of those made by Celestron, Orion, Sky-Watcher and others) and allow the use of many more common SCT accessories

For example, it allows you to use SCT threaded diagonals, visual backs, focal reducers and other accessories on your Mak-Cass telescope. The adapter has female Maksutov-Cassegrain threads on the inside  and male SCT threads on the outside at one end of the adapter. 

Note also that this adapter will NOT work the Celestron NexStar, C-90, C-130 and Meade ETX series of telescopes. Be sure to check the rear threads on your scope to confirm that it is 44.5mm and not the smaller 35mm size that is common with the Meade ETX and the Celestron Maksutov Nexstar Cassegrains. Be sure to use a millimeter ruler to determine correct thread size.