What is this? Take a guess and then read on:
It’s an eclipse of the sun by Phobos, one of the two moons of Mars, taken at three-second intervals by the Mars rover Curiosity on August 17th. As NASA describes it:
Images taken with a telephoto-lens camera on NASA’s Mars rover Curiosity catch the larger of Mars’ two moons, Phobos, passing directly in front of the sun — the sharpest images of a solar eclipse ever taken at Mars.
Phobos does not fully cover the sun, as seen from the surface of Mars, so the solar eclipse is what’s called a ring, or annular, type.
Curiosity paused during its drive that day to record the sky-watching images.
“This event occurred near noon at Curiosity’s location, which put Phobos at its closest point to the rover, appearing larger against the sun than it would at other times of day,” said Mark Lemmon of Texas A&M University, College Station, a co-investigator for use of Curiosity’s Mastcam. “This is the closest to a total eclipse of the sun that you can have from Mars.”
Incidentally, Curiosity is now starting to use autonomous navigation, a capability that lets the rover decide for itself how to drive safely on Mars, rather than being guided all the way by its handlers here on Earth.
“Curiosity takes several sets of stereo pairs of images, and the rover’s computer processes that information to map any geometric hazard or rough terrain,” said Mark Maimone, rover mobility engineer and rover driver at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The rover considers all the paths it could take to get to the designated endpoint for the drive and chooses the best one.”
Sort of the same thing you and I do when navigating from one side of the room to the other.