Craters Eminescu, Xiao Zhao and Eastman by VIRS and MDIS

The top image is a MASCS VIRS interpolated color composite of craters Eminescu (center), with Xiao Zhao and Eastman toward the east and in Mercury's mid-latitudes. The bottom image is a monochrome MDIS mosaic of the same area. Yellow areas correspond to high values in both the red and green channels, that is, high reflectance (at 575 nm) and high values of the 415-nm/575-nm reflectance ratio. In some cases these spectral characteristics are associated with fresh material (like the rays of Xiao Zhao) that has been less affected by space weathering. Hollows, such as those found on and around the central peak of Eminescu, have similar colors.

The VIRS composite shows hundreds of individual footprints tracks (minimum 100-200 m across and 3-4 km long) taken from different directions and altitudes. In locations where multiple footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map. In areas where footprints are sparse (separated by tens of km), observations are interpolated for complete coverage of the surface. In the MDIS mosaic, some brightness variations are due to tiling of images taken at different illuminations.

Date Created: June 16, 2014
Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS) and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Center Latitude: 10.0°
Center Longitude: 114.3° E
Resolution: 1 km/pixel
Scale: Eminescu crater(center) is about 130 km (80 mi.) in diameter

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