Curiosity watches as Mars' two moons eclipse the Sun
A solar eclipse is an amazing sight to behold, and it's an astronomical event that's not limited to Earth. NASA's Curiosity rover has captured images of Mars' two moons, Phobos and Deimos, as they passed between the Red Planet and the Sun.
In the same way we need to use special glasses to look at the Sun during a solar eclipse, so too does Curiosity. The rover's Mastcam is kitted out with special solar filters, allowing it to take some pretty fascinating shots of the Sun as the two small moons passed in front of it.
The first series of shots was snapped on March 17 this year, as Deimos transited the Sun. Because this moon is so tiny – a mere 1.5 mi (2.3 km) wide – it appears as just a black spot against the bright face of our parent star. Phobos is bigger, measuring about 7 mi (11.5 km) wide, but even it doesn't fully cover the Sun. That's known as an annular eclipse, which Curiosity captured on March 26.
The rover also saw the shadow of Phobos briefly darken the sky, in images taken by one of Curiosity's Navigation Cameras on March 25.
This isn't the first time Curiosity has encountered an eclipse, but the more times it does, the more data NASA scientists get to more accurately understand the eclectic orbits of Phobos and Deimos.
"More observations over time help pin down the details of each orbit," says Mark Lemmon, co-investigator on Curiosity's Mastcam. "Those orbits change all the time in response to the gravitational pull of Mars, Jupiter or even each Martian moon pulling on the other.
"Eclipses, sunrises and sunsets and weather phenomena all make Mars real to people, as a world both like and unlike what they see outside, not just a subject in a book."
Source: JPL NASA