Asteroid Ceres approaches Earth
February is a special occasion for the solar system's biggest asteroid. Not only is 1 Ceres making its closest approach to Earth since 1857, but it also will not get this close again for at least another millennium.
The long-term gravitational tugs of the planets conspire to modify Ceres' orbit just enough for this month's record-breaking event. Still, the difference between the asteroid's appearance now and at other favorable oppositions isn't huge. In 9 years, Ceres will be only 1.2 percent farther away.
You can follow Ceres through binoculars from your backyard. It sails through northern Leo during February, in a region without a lot of bright stars. Simply use the finder chart to pick out the pattern of nearby stars, then look for the interloper.
You may think this close approach will give you a chance to see Ceres without optical aid. You'd be right -- although not by much. At opposition, Ceres glows at magnitude 6.9 in a sparse starfield. Sharp-eyed observers under the darkest skies have seen objects this faint before. However, you'll have a better chance just 3 years from now. Ceres will then brighten to magnitude 6.7 thanks to the "opposition effect." The Sun-Earth-asteroid angle then will be closer to a straight line than during this month's slightly crooked arrangement. The better alignment in 2012 will increase Ceres' brightness more than the greater distance will decrease it.