While stitching together the original images to a higher resolution panorama (https://docs.google.com/open?id=0B2Y0xU4gYdrLd1BFNXJiT1JacUE https://docs.google.c

While stitching together the original images to a higher resolution panorama (https://docs.google.com/open?id=0B2Y0xU4gYdrLd1BFNXJiT1JacUE https://docs.google.com/open?id=0B2Y0xU4gYdrLd1BFNXJiT1JacUE - 50MB, 31K pixels wide, do not open the image in the browser, but download it, you've been warned.) I noticed a very clear difference in brightness between the left and the right end of it (the ends meet in the middle of the image, since I was recreating the angle that NASA chose). https://docs.google.com/open?id=0B2Y0xU4gYdrLUU5iMEMzSUdYUzg https://docs.google.com/open?id=0B2Y0xU4gYdrLUU5iMEMzSUdYUzg Looks to me like changes in weather during the time the pictures where taken.