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Today's offering shows two views of the crater Berkel. The image on the left is a monochrome image obtained when the Sun was lower on the horizon than when the color image on the right was collected. As a result, the left image emphasizes the topography of the surface (due to the presence of shadowing), whereas the image on the right is dominated by inherent differences in reflectance and color. The impact that formed Berkel excavated dark subsurface material and deposited it around the crater's rim. The presence of this low reflectance material causes the floor of the crater to appear black in the color image.
The image on the left is part of MDIS's high-resolution surface morphology base map. The surface morphology base map covers more than 90% of Mercury's surface with an average resolution of 250 meters/pixel (0.16 miles/pixel or 820 feet/pixel). Images acquired for the surface morphology base map typically have off-vertical Sun angles (i.e., high incidence angles) and visible shadows so as to reveal clearly the topographic form of geologic features.
The image on the right image is part of MDIS's color base map. The color base map is composed of WAC images taken through eight different narrow-band color filters and covers more than 90% of Mercury's surface with an average resolution of 1 kilometer/pixel (0.6 miles/pixel). The highest-quality color images are obtained for Mercury's surface when both the spacecraft and the Sun are overhead, so these images typically are taken with viewing conditions of low incidence and emission angles. The false-color presentation here has images taken through the 750-nm, 560-nm and 480-nm filters as red-green-blue.
Scale: Berkel crater is about 22 km (14 mi.) in diameter
Location: Berkel is located at -13.75° latitude, 26.9° E longitude
Instrument: Mercury Dual Imaging System (MDIS)
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Shown here is the first MESSENGER image from 2012! Though this image was acquired on January 1, it wasn't downlinked from the spacecraft until this week. The spacecraft has two solid-state recorders, which enable data to be stored on the spacecraft, and the mission uses a system of priorities to determine which data are downlinked. Often images are sent back to Earth within a few days of being acquired but occasionally longer times between image acquisition and downlink occur.
The year 2011 was an historic one for the MESSENGER mission, and there is much to look forward to in 2012. In 2012, the mission will continue to return new data from the Solar System's innermost planet nearly every day, completing its one-year primary mission in March and beginning new scientific observation campaigns in a one-year extended mission.
This image was acquired as part of MDIS's campaign to monitor the south polar region of Mercury. By imaging the polar region every four MESSENGER orbits as illumination conditions change, features that were in shadow on earlier orbits can be discerned and any permanently shadowed areas can be identified after repeated imaging over one solar day. During MESSENGER's one-year mission, MDIS's WAC is used to monitor the south polar region for the first Mercury solar day (176 Earth days), and MDIS's NAC is used for imaging the south polar region during the second Mercury solar day.
Date acquired: January 1, 2012
Image Mission Elapsed Time (MET): 0233869628
Image ID: 1207852
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -83.30°
Center Longitude: 41.44° E
Resolution: 298 meters/pixel
Scale: This image is approximately 300 kilometers (190 miles) across
Incidence Angle: 91.6°
Emission Angle: 8.7°
Phase Angle: 99.0°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This beautiful, unnamed crater is found within the Caloris impact basin, and formed partially atop another crater of similar size to its northwest. On the right-hand side of the image you can see the crater's central peak; at the upper left, you can see where the crater wall intersects what is left of the older crater's central peak.
Date acquired: December 24, 2011
Image Mission Elapsed Time (MET): 233221689
Image ID: 1177142
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 36.6°
Center Longitude: 166.4° E
Resolution: 29 meters/pixel
Scale: Scene is approximately 30 km (19 miles) across
Incidence Angle: 36.6°
Emission Angle: 33.1°
Phase Angle: 69.7°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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