03 March 2009
Credit: NASA/JPL/Space Science Institute
NASA recently published a wonderful image of Mimas, Saturn’s small icy moon. The image was acquired by the Saturn-bound Cassini spacecraft. The image shows an amazing space geometry: there are two terminators, regions of transition from the dark to light, on Mimas. One terminator, visible across the north, is due to sunlight, while the other terminator stretching across the east, is due to Saturn-shine, sunlight reflected off the giant ringed planet.
The spacecraft was looking toward the trailing hemisphere of Mimas (396 km across). North on Mimas is up and rotated 33 degrees to the right. Like our Moon, Mimas keeps one side turned to its parent planet. Intriguingly, Mimas orbits Saturn every 0.94 day, at an average distance of approximately 186,000 km.
This visual light image was taken on 23 January 2009, with the Cassini spacecraft narrow-angle camera. The spacecraft was approximately 508,000 km from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 152 degrees. Image scale is 3 km per pixel.
Further Reading
The Cassini-Huygens Mission to Saturn
http://saturn.jpl.nasa.gov/
Aymen Mohamed Ibrahem
Senior Astronomy Specialist