Can you tell that the two top images cover some of the same parts of Mercury? The top left image labeled "M2" was captured as the MESSENGER spacecraft looked back at Mercury while departing the planet after its second encounter. The view is eastward toward the limb (edge) of the planet. The top right image labeled "M3" was collected as MESSENGER approached Mercury for its third flyby. This time, the view is toward the western limb. The differing perspectives, foreshortening, and illumination conditions make it difficult to discern features visible in one image that also appear in the other. However, by placing the images into the same map projection the geometric distortion is largely removed. In the two lower views, the images are both in simple cylindrical projection, and we can recognize features common to both images. A few bright craters are labeled with letters to guide the eye. Images in map projection can be mosaicked together to produce a global image model of a planet's surface.
Date Acquired: October 6, 2008 and September 29, 2009
Image Mission Elapsed Time (MET): 131774782 and 162744226
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: The distance from "A" to "B" in the lower panel is about 300 kilometers (190 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.