Double Eclipse Captured: Earth, Moon Crossing Sun’s Face Seen By NASA Satellite

During the latest annular solar eclipse that occurred on Sept. 1, most of Africa and portions of Asia and Australia were treated to a partial eclipse, with the “ring of fire” visible only from a narrow strip across southern Africa and the Atlantic and Indian oceans. However, the most unusual view of the eclipse came from an entirely different location: NASA’s Solar Dynamics Observatory (SDO) that orbits Earth.

The view captured by the sensors of SDO was highly unusual despite it not capturing the annular eclipse. As opposed to a total eclipse — in which the shadow of the moon covers the entirety of the sun, as seen from Earth — the moon is relatively farther from Earth during an annular eclipse, thereby unable to block out the entirety of the sun, instead passing across its center and leaving, for a precious few seconds, a ring of the sun’s halo behind its shadow, colloquially called the “ring of fire.”

From its position and given its geosynchronous orbit, SDO’s line of sight of the sun gets blocked by Earth everyday for a few days twice a year. Which is another way of saying that from its point of view, there is a solar eclipse everyday for those days. Sept. 1 was one such day, and just as Earth was getting out of the way, SDO captured a rare event: the moon crossing across the sun’s face at the same time. A double eclipse.

The fuzzy blackness that passes across the sun first — moving from bottom right to upper left — is Earth, and the clearer shadow that shows up later — also moving in the same direction, but appearing smaller in the upper center — is the moon.

Earth’s shadow is fuzzy because of the atmosphere that absorbs some sunlight, while the moon leaves a clear shadow since it doesn’t have any atmosphere.