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The opposition of Mars is always an exciting time for planetary observers as it allows us the best view of our smaller neighbor. The opposition of Mars during this apparition occurs on January 29, 2010 at 19:27 UT. Unfortunately, the opposition of Mars this year (and the next opposition in 2012) will occur when Mars is near aphelion in its orbit, which occurs on March 30, 2010. Conversely, the Earth just passed perihelion in its orbit on January 3, 2010. Thus, even though Earth and Mars are passing close to each other in their respective orbits, they will pass by one another at a staggering distance of approximately 99,400,000 km. (This is nearly double the distance of the historic close approach in 2003 at a distance of approximately 56,000,000 km).

This year the closest approach of Mars to the Earth will occur on January 27, 2010 at 19:02 UT. At this time, Mars will lie at a distance of 99,329,832 km from the Earth and have an apparent diameter of 14.1 arcseconds. With steady skies and some magnification, observers should still have plenty of surface detail to observe. Syrtis Major and the Hellas Impact Basin will cross the central meridian of Mars approximately three hours before the closest approach. Use Sky and Telescope’s Mars Profiler to determine what features are on the central meridian during your observing time.