Double Impact Crater and Digital Elevation Model

The unnamed crater featured in this image might look like a ringed basin at high sun angles, but as can be clearly seen from the inset perspective view, in which the height is exaggerated 5 times, the central portion is a second crater that impacted the middle of the older crater. Such perspective views make use of a digital elevation model (DEM), which can be constructed either by accumulating topographic profiles from the MLA instrument or from measurements of shadows in images (or "photoclinometry"). In this case, the basemap is draped over the Gaskell DEM, which is constructed using photoclinometry. You can make your own perspective views of Mercury's surface using the QuickMap tool.

This image was acquired as part of MDIS's high-resolution stereo imaging campaign. Images from the stereo imaging campaign are used in combination with the surface morphology base map or the albedo base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 200 meters/pixel. Viewing the surface under the same Sun illumination conditions but from two or more viewing angles enables information about the small-scale topography of Mercury's surface to be obtained.

Date acquired: January 14, 2012
Image Mission Elapsed Time (MET): 234999326
Image ID: 1263152
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -42.23°
Center Longitude: 40.26° E
Resolution: 188 meters/pixel
Scale: The unnamed crater is ~83 km (52 mi.) across
Incidence Angle: 70.8°
Emission Angle: 22.9°
Phase Angle: 76.1°

Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington