Because CCD cameras are so much more sensitive than film, exposure times for planetary imaging are greatly reduced. Instead of several seconds for film, a CCD image can be obtained with exposures of 1 s or less, improving the ability to freeze the image. Most CCD cameras take only black and white images. To obtain color, separate exposures must be taken through red, green, and blue filters. Then the three images must be combined in a computer by using image-processing software. Because these images are going to be combined or stacked, it is important to obtain the three exposures without too much delay between images. Remember, Jupiter rotates rapidly. Therefore, CCD cameras with fast download times are advantageous. With the advent of software that will automatically align and stack images, many CCD imagers today take several images, tens if not hundreds, and stack them together. This stacking and aligning of multiple images accomplishes a couple of important things. Stacking multiple images increases the density of the image, which leads to an image of higher contrast and resolution. Some of the CCD images of Jupiter being produced today by skilled amateurs are of Voyager Spacecraft quality! Absolutely superb imaging showing great detail! Some amateur CCD images have even captured surface features on Jupiter's moons Ganymede and Io.
While CCD cameras are much more affordable today, the really good ones are still quite expensive. An adequate camera will cost at least several hundred dollars, and a really good one will cost several thousand. It is a wonderful research tool for those who can afford one.
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