Mercurian Terminator (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)

This striking image shows the progression of Daylight across the Surface of Mercury and the line separating the night from the day is called "Terminator". Scientists have studied interesting phenomena occurring near the Terminator of the Moon for years. Such occurrences involve the interaction between Lunar Dust and Charged Solar Particles (---> the Ions making the Solar Wind). Because Mercury's Regolith is exposed to almost ten times as many Charged Particles as the Moon, it is an excellent place to study the effects of Solar Radiation on Surface Materials. In this unprojected image, North is to the right.

This image was acquired as part of MDIS's campaign to monitor the South Polar Region of Mercury. By imaging the Polar Regions approximately every 4 (four) MESSENGER orbits as illumination conditions change, the Surface Features that were in the shadows on earlier orbits, can be discerned and any permanently shadowed areas can also be identified after repeated imaging over One Solar Day. During MESSENGER's one-year primary mission, MDIS's WAC was used to monitor the South Polar Regions for the first Mercury Solar Day (which corresponds to 176 Earth Days), and MDIS's NAC made repeated images of the South Polar Regions during the second Mercury Solar Day.

Date acquired: August 01, 2011
Image Mission Elapsed Time (MET): 220726567
Image ID: 579208
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 84.97° South Lat.
Center Longitude: 75,81° East Long.
Resolution: 1500 meters/pixel
Scale: the large crater at the bottom center is approx. 155 km (such as about 96 miles) in diameter.
Solar Incidence Angle: 84,9° (meaning that the Sun, at the picture was taken, was about 5,1° above the Imaged Local Horizon)
Emission Angle: 23,8°
Sun-Mercury-MESSENGER (or "Phase") Angle: 97,0°