I am currently using a C11 with a f6.3 reducer/corrector for deep sky visual. With that I have commenced using a Omega NPB filter which I screw in to the base of the eyepiece. In addition, I am looking at getting an O-III as well. This is obviously becoming a pain in the bottom of having to remove or change the filter depending on the objects I am viewing etc..... so I am tring to determine if there is something on the market, such as a filter wheel that you can use for visual use????
From doing a bit of research, most filter wheels have T-thread connectors, therefore by the time you fit all the necessary adapters to connect a 2 inch diagonal, it will blow away the spacing requirements for the reducer/corrector.....
