When trying to self guide I pick a guide star, the small box with the star appears and starts imaging the star. When I pick start the box will image the star once or twice and then go blank causing the guiding to stop and the image to download. I can switch to the guide CCD and focusing works like it should. Everything is normal, calibration, focusing, etc, until I start the self guide process. Yes the external CCD is picked, otherwise the guide CCD would not be able to focus on stars. Any suggestions, it almost seem like some sort of sorftware/computer problem. The same computer and CCDOPs works the selfguide feature of my STT8300 just fine.