Mars used to be of interest to astrophotographers only when it was at opposition and closest to Earth. That was before the webcam revolution, however. Today, talented imagers using high focal ratios like f/30, f/40, and higher are bringing back details of the Red Planet almost any time it is visible in the sky. Still, there's no denying that for most of us it's easiest to capture fine detail at opposition time. During 2003 I was a webcam novice, but thanks to the extraordinarily favorable opposition that summer I was able to capture some amazing details (Plate 73). The southern polar ice cap was not just visible; it changed shape in the pictures as it melted. I wasn't just imaging the famous dark "maria" of Mars. I was seeing detail within those areas, including hints of a prominent crater in Syrtis Major. Mars' stupendous shield volcanoes were often easy.
Plate 73. (Mars Polar Cap)
When Mars is at opposition much detail is visible to the eye and the camera, including the shapes of the polar ice caps. Credit: Author.
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