The terminator of Mercury, shown here in color, is the line between light and dark, or day and night. On Mercury, three days are equivalent to two years, or in other words, the planet spins around its axis three times for every two orbits around the Sun. The first Mercury year of the MESSENGER mission ended on Monday, June 13, 2011.

This image was acquired as 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 will cover 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 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. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing.

Date acquired: June 07, 2011
Image Mission Elapsed Time (MET): 215945273, 215943853, 215945277
Image ID: 349804, 349803, 349805
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 9 (1000 nanometers), 7 (750 nanometers), 6 (430 nanometers)
Center Latitude: -79.32°
Center Longitude: 173.9° E
Resolution: 1715 meters/pixel
Scale: Approximate width of the image is 1840 km (1140 mi.)

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.