When you buy a Takahashi telescope you are confronted with many different extension tubes and adapters to create different setups for photographic or visual use. Of all the thread sizes the Takahashi FS-60CB has to offer none fits the standard 2″ (48mm) filter threads used for most photographically useful astronomical filters.
Apparently when you buy the Camera angle adjuster, which allows rotation of the camera independently of the telescope, 52mm filters can be used.
A few days ago, when considering this mess, I played around with the various pieces, and found, that a 2″ filter can be put between the M56 Extension ring TKP20006B and the TKA00582 flattener or another M56 extension ring. There are no threads to put it on to, but if fits and, when the the extension ring and the flattener are screwed together, the filter sits firmly in place.
Of course the weather has not been cooperative and I have to wait to do a proper test on the night sky.