Astronomical CCD cameras utilize the same sort of CCD chips that are in your regular digital camera.  However, astronomical CCDs are much more sensitive than regular digital cameras, making them much more useful for imaging faint celestial objects.  This is the primary advantage of CCDs over digital cameras:  their increased sensitivity and much lower level of inherent electronic noise makes a world of difference when trying to image astronomical targets.

A typical CCD is around 20-50 times more sensitive than a DSLR, making for significantly reduced exposure times (and the associated decrease in the chance of something going wrong during the exposure).  This also mean imaging with less extra equipment, and an easier learning curve for beginners.  The linear response of some CCD chips make them useable for photometry, while DSLRs are not well suited to this application.

Another advantage of CCD imaging is the ability to image from moderately light polluted locations.  With film, it was always necessary to travel to a dark location away from the city to image.  With CCD imaging, it is possible to take images from light-polluted areas and digitally subtract most of the light pollution from the final image.  Also, light pollution and narrowband filters are more easily used with CCD cameras due to their increased sensitivity, making suburban imaging of very faint objects possible.

Return to FAQs