The August 1 solar eclipse from space
Posted by Emily Lakdawalla
01-08-2008 13:17 CDT
I probably should have posted something about today's solar eclipse before now, but I had assumed that, if you lived anywhere near the path of the eclipse, you would likely have heard about it, unless you live under a rock, in which case you're unlikely to be reading this blog. The path of totality passed primarily over Siberia and the Arctic Ocean, but good views of a partial eclipse were to be had across most of Asia and northern Europe.
The reason I'm mentioning it now is to point out that since an eclipse is caused by the passage of the Moon between the Sun and Earth, you can also see the effects of an eclipse from space. But, like an Earth-based observer, a spacecraft has to be in the right place at the right time to see it. Fortunately, we have the Terra and Aqua satellites in polar orbits, which provide frequently updated, highly detailed, almost instantaneously publicly released views of much of Earth, and Terra did happen to get an excellent look at the Moon's shadow as it was passing over the Arctic Ocean north of Siberia. (Aqua caught it, too, as it turns out, a little bit later.) The fact that this eclipse was close to the pole made it pretty likely that both satellites would catch it, since both are in polar orbits.The geometry of this image is pretty interesting. Most of the image is over ocean, but at the southern edge the image crosses into Northern Europe. If MODIS were a framing camera like the one you likely have at home, we'd see the Moon's shadow as a round spot (distorted slightly into an ellipse because Earth's surface angling away from the cast shadow). However, MODIS is a "pushbroom" camera, scanning lines of the image sequentially as its orbit carries it across Earth, so both the spacecraft and the Moon's shadow were moving throughout the exposure, which is why the shadow appears all stretched out. The image was taken from about 09:30 to about 09:45 UTC. Thanks to Doug Ellison for the tip on these images!
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