Hayabusa2 views Earth and the Moon on approach to December 3 flyby
I just love photos of Earth from planetary missions -- especially if they manage to get Earth and Moon in the same shot, as Hayabusa2 did on November 26. Hayabusa2 is on the way in to a flyby of Earth on December 3 at 10:07 UT. You can watch a realtime simulation here.
JAXA / Emily Lakdawalla
Hayabusa2 image of Earth and the Moon, November 26, 2015
Hayabusa2 used its optical navigation telephoto camera (ONC-T) to capture this view of Earth and the Moon together on November 26, 2015 at 03:46 UT, or 12:46 Japan time. The image is made of three distinct images captured through red, green, and blue filters, and has been processed to align the different-filter images with each other. North is to the left; Asia and Australia are visible on the lit face of Earth. Hayabusa2 was on the way in to its December 3, 2015 flyby of Earth.
I did a little bit of processing on this image; like most spacecraft cameras, Hayabusa2's Optical Navigation Camera gets color information by rotating a filter wheel in front of a monochrome detector, and we back on Earth must assemble those component images into a color photo. When the targets are moving, there are often color fringes around the edges of the objects, so I worked on the image a bit in order to reduce those color fringes and make the photo a little more visually pleasing. Pleasing to me, anyway. Perhaps not everyone is bothered by these tiny details!
Anyway, whenever I see an image of Earth, I always want to know which face of Earth I'm looking at. Since it was taken at 12:46 Japan time, you know that Japan is near the middle of the sunlit part of the disk. I was thrown off a bit by how gibbous it looks -- but it's important to remember that we're getting pretty close to the winter solstice in the northern hemisphere. Happily, I have a cool new tool available for seeing what portion of Earth is sunlit at any given (recent) time and date: the DSCOVR spacecraft, which is parked at the Earth-Sun L1 point and regularly sending us fully-lit global images of Earth using its EPIC instrument. Here is the photo from DISCOVR EPIC that was taken closest to the time of the Hayabusa2 image: