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The top image is a MASCS VIRS interpolated color composite of craters Munch and Sander (center), with Poe toward the east. These craters are in the north of Caloris basin. The center image is a MASCS color composite showing individual spectral footprints. The bottom image is a monochrome MDIS mosaic of the same area. The three crater rims are blue, indicating low reflectance. Sander's floor is yellow, however, which is high reflectance and indicative of fresh material.
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. This is particularly true in the northern hemisphere, where Caloris is located. 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: 42.5°
Center Longitude: 154.5° E
Resolution: 1 km/pixel
Scale: Sander crater (center) is about 50 km (31 mi.) in diameter.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image features a stunning view of two complex craters within the Caloris basin. The floor of Sander crater is covered with bright hollows, while Munch crater stands out due to its low-reflectance crater rim.
This image was acquired as a high-resolution targeted color observation. Targeted color observations are images of a small area on Mercury's surface at resolutions higher than the 1-kilometer/pixel 8-color base map. During MESSENGER's one-year primary mission, hundreds of targeted color observations were obtained. During MESSENGER's extended mission, high-resolution targeted color observations are more rare, as the 3-color base map covered Mercury's northern hemisphere with the highest-resolution color images that are possible.
Date acquired: April 26, 2014
Image Mission Elapsed Time (MET): 40804465, 40804485, 40804469
Image ID: 6194731, 6194736, 6194732
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: 39.98°
Center Longitude: 153.1° E
Resolution: 290 meters/pixel
Scale: Sander crater is about 51 km (31.7 miles) in diameter
Incidence Angle: 46.9°
Emission Angle: 50.5°
Phase Angle: 79.7°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's color image highlights the bright hollows on the floor and peaks of Sander crater, named after the German photographer August Sander. The process responsible for these bright, shallow formations is still unknown, but it is possible that volatile sublimation is etching away at the surface.
This image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new campaign that began in March 2013 and that utilizes all of the WAC's 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.
Date acquired: June 06, 2013
Image Mission Elapsed Time (MET): 12802777, 12802773, 12802771
Image ID: 4204118, 4204116, 4204115
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: 42.53°
Center Longitude: 154.2° E
Resolution: 265 meters/pixel
Scale: Crater diameter is about 51 km (31.7 miles)
Incidence Angle: 42.9°
Emission Angle: 26.5°
Phase Angle: 69.4°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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