While a series of WAC [Wide Angle Camera] calibration images of the Earth were being acquired, the Narrow Angle Camera (NAC) was shuttered to capture this spectacular Earth view. The bottom of the Earth was clipped because the prediction of the exact time when the cameras' fields of view would cross the Earth was off by a few seconds.
Since the NAC acquires only one line of a picture at a time, the spacecraft had to be nodded across the Earth to build up the scene. The NAC Earth view is actually a mosaic of NAC-Left and NAC-Right images put together after calibration. The distance between the Moon and the Earth was 372,335 km when the picture was taken, with a pixel scale of about 3.7 km, and the center of this view of the Earth is 25°N latitude, 114°E longitude (a few hundred kilometers north of Hong Kong).
It was a beautiful clear summer day over the North Pole, you can see ice covering most of the Arctic Ocean with a few leads of open water (dark) starting to open up. If you look very closely you can follow the Lena River upstream from the Arctic Ocean all the way to Lake Baikal. Much of the Middle East was clear and you can trace spectacular swirl patterns of folded rock layers through Iran, Afghanistan, and Pakistan (geology knows no borders!). These mountains formed as the Eurasian and Arabian tectonic plates collided.
Photo credit: NASA / GSFC / Arizona State University
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