Vixen clamp on Dobsonian tube

[Commanderfish]

Hi,

Has anyone fitted a Vixen clamp to the outside of their dob tube in place of the finder shoe?  This would enable me to mount a small frac as a finder scope.  Someone must have done this I'm sure, so the question is can you bung any old Vixen clamp on or do you need one with a curved base?  My Dob is a 16" (around 430 mm external diameter).

 

Cheers!

[Commanderfish]

A little bump - anyone got any ideas on this?  As the screws on the existing standard Synta finder shoe base are quite close together, should I simply buy a normal flat bottomed Vixen clamp and bung it on?  Or do I need some kind of curved base adapter?

[bomberbaz]

I did this using an f4.5 60mm frac. Clamped a shoe to an orion twin mount then mounted frac to scope using the extra large spotting scope mount. Think i got the gear from 365 astronomy.