[billdan (Bill)]

Hi Stefan,

If your focal reducer is threaded it should screw into the TOAG and the focal reducer is inserted into your focuser. Well that's how it works with a Baader MPC coma corrector.

Then you may need to use a spacer between the TOAG and the DSLR, to get the correct backfocus for the reducer. So get this bit working OK first so the reducer is working at optimum.

Then you position the prism in the TOAG so it does not create a shadow on the CCD chip in the DSLR.

Plug in your guide camera, focus on a star with the DSLR and then move the guide camera (in or out) until its focus point is the same as the DSLR.

Sounds easy but it can be frustrating to get it perfect.

EDIt: Be careful with the prism I had it fall out onto the grass once, took me ages to find it in the dark, and then I installed it back to front which took me another 30mins to figure out why I wasn't getting any picture from my guide cam.

Cheers
Bill