On May 25, 2017, NASA’s Solar Dynamics Observatory had a little surprise. They saw the moon blocking out the sun in a solar eclipse.

The moon crosses the sun in during a partial solar eclipse in space in this view from NASA’s Solar Dynamics Observatory in space. The lunar transit lasted nearly an hour, with the moon covering about 89 percent of the sun’s disk at the eclipse’s peak. Credit: NASA Goddard Space Flight Center/SDO/Joy Ng, producer

“The lunar transit lasted almost an hour, between 2:24 and 3:17 p.m. EDT, with the moon covering about 89 percent of the sun at the peak of its journey across the sun’s face. You can see the moon’s crisp horizon from this view. That’s because the moon has no atmosphere to distort the sunlight” NASA wrote.

Let’s talk a little about the NASA’s Solar Dynamics Observatory. You may think that the observatory will just watch our Star, but its mission is complex. It investigates how the sun generates its magnetic field. Also, how it’s structured and what happens when it burps magnetic energy out into space.

Later this summer on Aug. 21, 2017, SDO will witness another lunar transit. But the moon will only barely hide part of the sun. However, on the same day, a total eclipse will be observable from the ground. A total solar eclipse — in which the moon completely obscures the sun — will cross the United States on a 70-mile-wide ribbon of land stretching from Oregon to South Carolina. Throughout the rest of North America — and even in parts of South America, Africa, Europe and Asia — a partial eclipse will be visible.