English: Instrument: Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)

Scale: Dominici is 20 kilometers (12.4 miles) in diameter; Homer is 314 kilometers (195 miles) in diameter Projection: The image on the left is a portion of the global Mercury mosaic. The image on the right comes from a high-resolution WAC sequence taken during MESSENGER’s second Mercury flyby. Both are at a resolution of 500 meters/pixel (0.3 miles/pixel).

Of Interest: The small rayed crater to the immediate right of the center of the left image is Dominici, named in March 2010 for Maltese sculptor and painter Suor Maria de Dominici (1645-1703). Dominici’s bright rays indicate that it is relatively young, and the young rays appear light blue in enhanced-color images, as seen in the image to the right. Dominici also has bright material on its floor and is surrounded by crater ejecta and material that appears orange in enhanced color. These color differences, as in nearby Titian crater (white arrow), suggest that the impact crater excavated material from beneath Mercury’s surface that differs in composition from the surrounding surface. Dominici lies within a much larger impact structure, the Homer basin, indicated by the white circle in the right-hand image. Homer received its name after the Mariner 10 mission, which imaged Homer under different lighting conditions that showed well the basin but not as clearly the bright rays of Dominici.