Why do some people use CCD cameras for astronomical imaging instead of digital cameras?
Heat generates noise in CCD (charge coupled device) chips. Many deep sky objects require long exposures, during which noise can easily exceed the signal you are trying to capture. CCD cameras for astronomical imaging use Peltier devices (solid-state heat pumps) to cool CCD chips to temperatures at which they can be operated for long-exposure imaging with minimal noise. There are other benefits to how CCD cameras are designed. For example, they can have more sophisticated electronics with functionality geared specifically toward astronomical imaging (e.g. anti-blooming gates, pixel binning), and more robust designs that can better withstand exposure to temperature extremes and humidity.
