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Acquiring high-incidence-angle images of Mercury's surface is a major mapping activity in MESSENGER's extended mission. The high-incidence campaign compliments the surface morphology base map of MESSENGER's primary mission, which was acquired under generally more moderate incidence angles. High incidence angles, achieved when the Sun is near the horizon, result in long shadows that accentuate the small-scale topography of geologic features. The high-incidence-angle base map is being acquired with an average resolution of 200 meters/pixel.
This image is part of the high-incidence campaign and shows part of Jokai crater, a 93 km (58 mi.) diameter complex crater named for the 19th century Hungarian novelist Mor Jokai. Two smaller craters overprint the rim of Jokai. Jokai itself overprinted a similarly-sized crater, and part of the remaining older crater's wall can be seen towards the left side of this image.
Date acquired: April 11, 2012
Image Mission Elapsed Time (MET): 242631251
Image ID: 1633957
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 71.3°
Center Longitude: 224.0° E
Resolution: 173 meters/pixel
Scale: The small, shadowed crater at the center of the image is approximately 14 km (8.7 mi.) in diameter.
Incidence Angle: 80.4°
Emission Angle: 11.2°
Phase Angle: 69.1°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Here we have two images of the impact crater named Debussy. The one on the left is from MESSENGER's monochrome base map. The one on the right is a complement from the stereo base map. Because of the differing viewing perspectives, the images can be combined to derive an elevation map (digital terrain model) of the surface.
The left image was acquired as part of MDIS's high-resolution surface morphology base map. The surface morphology base map will cover 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 right image was acquired as part of MDIS's high-resolution stereo base map. The stereo base map is used in combination with the surface morphology base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 250 meters/pixel (0.16 miles/pixel or 820 feet/pixel) or better. During MESSENGER's one-year mission, the surface morphology base map is acquired during the first 176 days, and the second 176 days are used to acquire the complementary stereo base map, which includes the image here.
Left image:
Date acquired: July 31, 2011
Image Mission Elapsed Time (MET): 220581440
Image ID: 572963
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -34.04°
Center Longitude: 11.25° E
Resolution: 284 meters/pixel
Incidence Angle: 67.2°
Emission Angle: 35.2°
Phase Angle: 102.4°
Right image:
Date acquired: January 19, 2012
Image Mission Elapsed Time (MET): 235424544
Image ID: 1283627
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -33.95°
Center Longitude: 13.18° E
Resolution: 161 meters/pixel
Incidence Angle: 76.9°
Emission Angle: 23.3°
Phase Angle: 89.2°
Scale: Debussy crater has a diameter of about 80 km (50 mi.)
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
For Valentine's Day, it seems appropriate to feature Shakespeare basin, named for the English poet and playwright and author of a famous collection of sonnets, some focusing on love. "Shall I compare thee" to other large basins on Mercury? If so, check out Rembrandt, Tolstoj, Rachmaninoff and Beethoven.
This mosaic was assembled from eight images that were acquired as part of MDIS's high-resolution surface morphology base map. The surface morphology base map will cover 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.
Date acquired: April 26 - 28, 2011
Image Mission Elapsed Time (MET): 212372542, 212415875, 212416002, 212459333, 212459461, 212459565, 212502921, 212503025
Image ID: 181841, 183945, 183946, 185952, 185953, 185954, 188123, 188124
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 48.5°
Center Longitude: 208° E
Resolution: 240 meters/pixel
Scale: Shakespeare basin has a diameter of 400 km (250 miles)
Incidence Angle: 73°
Emission Angle: 0.6°
Phase Angle: 75°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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
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