Image: NASA's SDO spots a lunar transit
On Oct. 19, 2017, the Moon photobombed NASA's Solar Dynamics Observatory, or SDO, when it crossed the spacecraft's view of the Sun, treating us to these shadowy images. The lunar transit lasted about 45 minutes, between 3:41 and 4:25 p.m. EDT, with the Moon covering about 26 percent of the Sun at the peak of its journey. The Moon's shadow obstructs SDO's otherwise constant view of the Sun, and the shadow's edge is sharp and distinct, since the Moon has no atmosphere which would distort sunlight.
SDO captured these images in a wavelength of extreme ultraviolet light that shows solar material heated to more than 10 million degrees Fahrenheit. This kind of light is invisible to human eyes, but colorized here in green.