If you want to be able to attach 2" accessories(e.g. a 2" diagonal) to your FS-60C, get the Tak 2" compression ring adapter for the FS-78 or the Tak 2" ocular adapter for the FS-78 which is similar but uses two thumb screws instead of a compression ring.
Anacortes sells both and lists them in the "Adapters" section within "Accessories".
Among other things, the adapter will permit use of 2" eyepieces with the scope and allow it to make full use of its wide field capabilities.
I have never tried putting one on mine but you can read this if you want. I have the 1/12th wave Tak 2" Tak diagonal (TK-TSD0001) for my FSQ but I never bought the so called Novoselsky adapter to allow it to work with the FS-60C (as in the article):
I also read that a 2X barlow with the FS60 is better than the extender lens made by Tak which must be screwed onto the focuser each time its used. A Vixen "T" barlow - which cost about 1/8 as much as the Takahashi FS60 extender is supposed to work great. I haven't tried this as I have the extender for my FSQ already.
Doing a quick search, this is the only link I could find on the Vixen T-Thread barlow:
What you are looking for is the Tak 2" compression ring adapter http://buyusedtelescopes.com/product.asp?t=&pid=2415&m=35 It basically screws on to the back of the scope and lets you put on any 2" or 1.25" adapter on your baby Tak without having to buy all the other Tak adapters. Here it is mounted on my scope http://www.pbase.com/panotaker/image/55120757 The only thing is that a 2" diagonal wont come to focus with it with some eyepieces. To make a 2" eyepiece come to focus, you need the other shorter adapter that someone else recommended, and then you will also need a high dollar Tak diagonal to go along with it. I just use a 24 pan on a 1.25" diagonal for wide views. Ralph