Total eclipse of the sun
This image captures a 2002 eclipse as seen from Australia while the Solar and Heliospheric Observatory (SOHO) spacecraft was taking pictures of the sun. A solar eclipse happens when the moon passes between the sun and the Earth. As NASA reports, solar eclipses give space agencies the rare opportunity to study the outer coronas of the star. As one source notes, a total eclipse "occurs when the dark silhouette of the moon completely obscures the intensely bright disk of the sun, allowing the much fainter solar corona to be visible."