Planetary Imaging Cameras
The planets are very bright objects from an astronomical perspective, so long exposures are not necessary. Anyone who has spent any time observing the planets at high magnification knows that they tend to slip in an out of focus do to turbulence in the atmosphere, which is a phenomena that astronomers refer to as "seeing." Using a video camera with a fast frame rate allows you to quickly gather many individual photo frames, some of which will be in sharp focus while others are not. Most planetary cameras are supplied with Registax image processing software, which is capable of sifting through video frames to separate the good frames from the bad, and automatically stack the good frames to create a composite image.
CMOS based cameras have two primary advantages over their CCD counterparts that are important to planetary imaging. First, they require far less power, meaning they can be powered directly through the USB port of their supporting PC or tablet device. Second, the readout speed of a CMOS sensor is far greater than that of a CCD sensor, which is essential to achieving high frame rates. The higher the frame rate, the greater the probability of catching in-focus frames during those fleeting moments of excellent seeing conditions.
While not important from a technical perspective, CMOS sensors are far more economical to produce than CCD sensors. As a result, the very best planetary imaging cameras cost less than the least expensive CCD cameras available today. Given the extremely short exposures involved, there is also no reason to worry about the added cost of an autoguider and guide scope; altazimuth mounts are perfectly suitable for plantetary imaging so long as they are capable of tracking the target.