What else do I need....?

You need to learn what you are doing. A Dob is the name of the mount. You can't put a dobsonian mount on an equatorial mount. You need accurate tracking motor. The equatorial mount with proper tracking to be used for astrophotography, and capable of supporting a 10 inch reflecting optical tube, will cost several thousand dollars even if you find a good used one. My advice is SLOW DOWN. Find a good local club to join and learn about the equipment and the night skies before you undertake something as difficult as astrophotography.