This image of M101 is the first taken with two cameras working simultaneously.
One camera, STL-1000M, on Takahashi TOA-150 @ f/7.3 for luminance data and the other, Canon 60Da, on Takahashi FSQ-106N @ f/5.0 for RGB data.
The main camera is the STL. It is controlled by CCDCommander and CCDSoft, with the main chip used for luminance acquisition and the secondary chip for guiding (and dithering). Read more