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Have You Ever Had It Blue
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Have You Ever Had It Blue?

April 29, 2013
Release Date: April 25, 2013 Topics: Albedo Contrasts, Low Reflectance Material (LRM), Named Craters, Smooth Terrain, Volcanism, WAC Date acquired: July 09, 2011 Image Mission Elapsed Time (MET): 218671363, 218671371, 218671365 Image ID: 480913, 480918, 480914 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: 47.75° Center Longitude: 123.5° E Resolution: 908 meters/pixel Scale: The edges of the image are about 220 km (136 mi.) long. Incidence Angle: 51.3° Emission Angle: 0.4° Phase Angle: 50.9° The image was binned on the spacecraft from its original 1024 x 1024 pixel size to 256 square in order to reduce the volume of data that needed to be stored on the recorder and transmitted to Earth. Of Interest: Today's image is centered on a large unnamed crater to the northeast of Dali. The crater has been flooded with smooth plains that have a relatively high reflectance and reddish color compared to the average surface of Mercury. The surrounding area, by contrast, has low reflectance and blue color. The high-reflectance red material and the low-reflectance blue material are the two major color-compositional types on Mercury. This image was acquired as part of MDIS's 8-color base map. The 8-color base map is composed of WAC images taken through eight different narrow-band color filters and covers more than 99% of Mercury's surface with an average resolution of 1 kilometer/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 MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington