Eclipses Seen From Orbit

SDOEarthEclipse-LunarTransit2013NASA’s Solar Dynamics Observatory (SDO) recently entered its semiannual eclipse season, a period of three weeks during which Earth blocks its view of the sun for a part of each day. Yesterday, SDO observed two transits. Earth blocked SDO’s view of the Sun from about 06:15 to 07:45 UTC, and from around 11:30 to 12:45 UTC, the Moon moved between the satellite and the Sun for a partial eclipse.

The edge of Earth’s shadow appears fuzzy. That’s because some light from the Sun comes through Earth’s atmosphere. The shadow line of the Earth appears almost straight because the Earth is much closer to SDO and appears to be larger than the Sun.

Because the moon has no atmosphere, its curved shape can be seen clearly, and the line of its shadow is crisp and clean. Any spacecraft observing the sun from Earth orbit has to deal with such eclipses, but SDO‘s orbit is designed to minimize their interference.

Image Credit: NASA

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