The Curiosity rover turned its cameras upward for a first-ever clear, daylight color photograph of Phobos over Mars.
Note: The black dot to the left of Phobos is just a bad pixel. The color of the overall image is characteristic of the Martian sky with a low dust load - under totally clear conditions, the sky is slate-gray at the zenith due to the thinness of the atmosphere and pales to a somewhat brighter shade closer to the horizon. Blown up:
Sky conditions on Mars are mostly differentiated by how much dust is in the air. The dirtier it is, the more pinkish/orange it is - with the shade differing from the zenith to the horizon, and of course with time of day. So when there's little or no dust, it's just what the super-thin air can refract, which means no pink or orange - just shades of fathomless gray. The above photos reflect relatively clear conditions in the evening sky. I suppose dust could often make it too dim to see easily.
Deimos - the smaller, farther moon - is too small and far away to be more than a speck even under ideal viewing conditions, so it wouldn't be much to see. Although Phobos is considerably smaller in the sky than Earth's Moon, it moves a lot faster because it's only 9,300 km above the ground - it crosses the entire sky in a bit over 4 hours.
It's about time NASA took such an image - I've found it irritating and dumbfounding that it just never occurred to them before now in all the years of roving the Martian surface to turn the camera up and take a plain old photograph of the sky with Phobos in it. I can only speculate that maybe the cameras on the smaller twin rovers, Spirit and Opportunity - the latter of which is still in operation - aren't fast enough to capture Phobos, or maybe can't pivot enough to get the viewing angle. They have captured transits of the Sun by Phobos, but that only requires very simple light-sensing.
Still, oftentimes it seems like NASA loses sight of the fact that they're not just there to do pure science and answer the abstruse questions of geologists and chemists - they're there to serve as the projected eyes of all humanity, to see what we can't yet see for ourselves: To bring another world to us, because we can't yet be there. I'm glad some small measure of that most fundamental of missions is finally seeping into their awareness, through what I'm sure is the daunting fog of technical details they have to manage.
I'm sure others have also shown these additional self-portrait views of Curiosity beyond the ones I had shown earlier here - they were all released several weeks ago - but I just find these mesmerizing and worth showing, even if they've already been seen. They're like some incredibly vivid steampunk dream:
The equipment seems like something that would be appropriate strapped to the back of Peter Venkman and Egon Spengler. Curiosity is nuclear, after all. Every bit of that thing is pure 21st century function, but it looks like art - technology having circled back around to Jules Verne.