If you want full control over two cameras, including the ability to dither, you can check out this software developed for me by Tom How. You can use two copies of TheSkyX running on the same computer:
http://astro.neutral.org/software/mu...t-TheSkyX.html
Peter
ATT article I wrote on dual scope setup
https://drive.google.com/file/d/0BwR...48-cA4vRZzNKsw