The Atlas mount is rated for 40 lbs. I had 50 lbs on it between the 10 inch Newtonian plus guide scope and cameras. It almost worked - I had some flexure in the system that cause a slight trailing off stars which I fixed in Photoshop. I think I'll stick with an 8 inch Newtonian as the biggest this mount can comfortably handle for long exposure imaging.

Acquisition Details:
Date: 05/20/2007
Exposure: L: 15x2 min + 15x1 min, RGB: 15x2 minutes
Telescope: DBA Certified 10 inch f/5 Newtonian + MPCC
Mount: Atlas EQ-G
Camera: SXV-H9