This provides another vixen finder dovetail mount that can be used for a guidescope or additional astro camera.
Simply clamps to the outside of the astro-tech AT72ED (original),using a few screws and nuts.
The vixen dovetail uses #6 screws and nuts (imperial), the nuts require a little work with a file to get them in place.
The clamp part uses #8 screws and nuts. I am sure you can figure out the metric equivalent.
Enjoy,