Jupiter is probably the most consistently interesting planet for the Solar System imager. With the coming of the webcam, the planet went from being a distant and difficult subject where amateurs struggled to get convincing pictures of cloud bands and the Great Red Spot, to a world of riotous detail (Plate 53). Even amateurs not blessed with superb seeing can bring back good Jupiter images almost any time the planet is visible. What makes that possible is Jupiter's huge size. With an angular size of as much as 45 arc seconds, the planet is large enough to reveal considerable detail in webcam pictures taken through a C8 at the fairly low focal ratio of f/20 (with a 2x Barlow, that is). Being able to keep focal length/magnification low helps with seeing problems. The only particular problems Jupiter hold for the imager concern focusing and exposure. Jupiter, as mentioned earlier, presents a less hard-edged limb than the Moon or Mars, making it more difficult to focus. It never looks quite sharp. Solution? Spend plenty of time focusing. Pay attention to the clarity of detail on the disk and K3CCD's exposure level "meter." How long an exposure? It's good to have plenty of frames, but Jupiter spins rapidly, rotating once on its axis in 9.8 hours. To avoid blurring, keep .avi length to 90 seconds or less.
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