Bob Moler's Ephemeris Blog

Ephemeris for Friday, February 15th.  The sun will rise at 7:42.  It’ll be up for 10 hours and 29 minutes, setting at 6:11.   The moon, 2 days before first quarter, will set at 12:29 tomorrow morning.

The asteroid 2012 DA14 will zip inside the ring of geosynchronous communication and weather satellites this afternoon around 2:30.  We’re on the wrong side of the earth to see it.  But many astronomers with optical and radio telescopes will be watching.  The asteroid, perhaps half the size of a football field in diameter will whiz by 18,000 miles above the earth’s surface and from our point of view will appear to move from south to north.  The asteroid was found by Spanish amateur astronomers in a program to refine the orbits of other near earth objects.  They use mostly their own funds and whatever they receive in donations.   The asteroid was discovered with a CCD camera that they received with a grant from the Planetary Society.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

The Bad Astronomer, Phil Plait, has a lot to say about today’s close encounter.

The orbit of asteroid 2012 DA14 as it passes the earth on February 15, 2013. Credit NASA.

As it passes the earth the asteroid 2012 DA14 will appear to travel just about directly south to north.  This because we are orbiting the sun too.  Until the encounter the asteroid has a slightly slower orbit of the sun.  The encounter will cause the orbital period of the asteroid to shorten.  The asteroid will cross this point in the solar system again, and someday the asteroid and the earth will cross each other’s path again on or around February 15th in a distant year.