Mars has two moons, but they don’t have much in common with Earth’s moon except that they orbit a planet. Curiosity spends most of its time scanning the Martian surface, but NASA couldn’t pass up the opportunity to capture a particular event for the first time. Pointing its camera upward, Curiosity captured a 41 image series that shows one of Mars’ moons eclipsing the other.The images were taken with the telephoto-lens of Curiosity’s Mastcam instrument on August 1st. Prior to the event, NASA scientists realized the moons were going to cross paths shortly after the rover woke up to transmit data back to Earth. That made it simple to snap the photos without delaying any experiments. Although, the images had to wait a few days to make it through the upload queue as more important images were sent home. NASA apparently doesn’t take the cool-factor into account when assigning priority.The still photos were stitched together to create a video of the event. The video shows the larger moon, Phobos, passing through the frame and in front of the smaller moon, Deimos. Both moons orbit much closer to Mars than our moon does to Earth, so despite its small size, you can pick out details on Phobos’ surface. Phobos would look roughly half the size of Earth’s moon in the Martian sky, though it is only 1% the size of the moon (about 6.9 miles across).Phobos and Deimos are far too small to become spherical — they’re essentially asteroids that have been captured by Mars. It doesn’t matter that they’re not very big, or very round. Curiosity filmed a video of an alien eclipse, and that’s pretty cool.