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Hidden Hollows
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Hidden Hollows

October 3, 2013
Release Date: October 2, 2013 Topics: Color Images, Hollows, Named Craters, WAC Date acquired: August 13, 2011 Image Mission Elapsed Time (MET): 221758501, 221758509, 221758503 Image ID: 628307, 628312, 628308 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: -12.53° Center Longitude: 78.18° E Resolution: 623 meters/pixel Scale: Steichen crater is 196 km (122 mi.) in diameter. Incidence Angle: 48.3° Emission Angle: 0.2° Phase Angle: 48.2° Of Interest: The large, older crater featured in today's image is Steichen. At almost 200 km (124 mi.) across, Streichen is a complex impact basin, with a central peak ring that is partially buried by smooth crater floor deposits. Though much of the northwestern central peak ring is buried, one tiny, bright blue speck surrounded by a dark blue halo pokes up through the smooth floor deposits, hinting that hollows might be forming in a little patch of excavated low-reflectance material. 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