Vesta the brightest asteroid reaches opposition this year in Taurus on December 9th. The asteroid is easy to locate as it is currently positioned close to Jupiter and first magnitude orange/red star Aldebaran, the brightest star in the constellation. This month Jupiter also reaches opposition and at magnitude -2.8, the giant planet dazzles and dominates the night sky.
Vesta can on occasions reach 5th magnitude and therefore naked eye visibility, but this time it does not attain such brightness. On December 9th, the asteroid peaks at magnitude 6.4 and although just below naked eye visibility, it is still a very easy binocular / small telescope target, even from relatively light polluted areas. Since Vesta travels quickly against the "fixed" background stars, its movement can be tracked even on a nightly basis.
Vesta was the fourth asteroid to be discovered on the 29th March 1807 by the German astronomer Heinrich Wilhelm Olbers. Along with the other asteroids known at the time (Ceres, Pallas and Juno), Vesta was initially classified as a planet in its own right and subsequently was given its own planetary symbol. With further discoveries, all in the region between Mars and Jupiter, the general term asteroids was coined to describe them. Much later in 2006, the International Astronomical Union (IAU) defined a new classification of dwarf planet of which the largest asteroid Ceres is now a member.
Despite being only the third largest body in the main asteroid belt with a diameter of 530km (330 miles), Vesta is the brightest asteroid. It appears brighter than even the much larger dwarf planet Ceres and the slightly larger asteroid Pallas. This is because its approaches closer to the Earth than the other two and also has a much higher reflective surface. At favourable oppositions, the maximum visual magnitude of Vesta is 5.1 and therefore easily within naked eye visibility, especially from a dark site.
At opposition this year, Vesta will peak at magnitude 6.4.
The beautiful zodiac constellation of Taurus is where to find Vesta in December. The famous constellation represents the head and shoulders of a bull, depicted as charging at neighbouring Orion. Aldebaran denotes the magnificent red eye of the bull with Vesta located only a few degrees to the east. Surrounding Aldebaran is the famous Hyades open cluster and located about 20 degrees to the northwest of Vesta is the most famous open cluster in the sky, The Pleiades (M45). Unmistakable Jupiter is a few degrees north and west of Vesta.
Vesta Data Table
|Date||RA (J2000)||DEC (J2000)||Apparent Magnitude|
|November 26,2012||05h 21m 49s||17d 31m 29s||6.7|
|November 27,2012||05h 20m 49s||17d 32m 08s||6.7|
|November 28,2012||05h 19m 48s||17d 32m 50s||6.7|
|November 29,2012||05h 18m 46s||17d 33m 32s||6.6|
|November 30,2012||05h 17m 43s||17d 34m 17s||6.6|
|December 01,2012||05h 16m 40s||17d 35m 04s||6.6|
|December 02,2012||05h 15m 36s||17d 35m 52s||6.6|
|December 03,2012||05h 14m 31s||17d 36m 42s||6.5|
|December 04,2012||05h 13m 26s||17d 37m 34s||6.5|
|December 05,2012||05h 12m 20s||17d 38m 28s||6.5|
|December 06,2012||05h 11m 14s||17d 39m 24s||6.5|
|December 07,2012||05h 10m 08s||17d 40m 21s||6.5|
|December 08,2012||05h 09m 01s||17d 41m 21s||6.5|
|December 09,2012||05h 07m 54s||17d 42m 22s||6.4|
|December 10,2012||05h 06m 47s||17d 43m 25s||6.4|
|December 11,2012||05h 05m 40s||17d 44m 30s||6.5|
|December 12,2012||05h 04m 34s||17d 45m 38s||6.5|
|December 13,2012||05h 03m 27s||17d 46m 47s||6.5|
|December 14,2012||05h 02m 21s||17d 47m 58s||6.5|
|December 15,2012||05h 01m 15s||17d 49m 11s||6.5|
|December 16,2012||05h 00m 09s||17d 50m 27s||6.5|
|December 17,2012||04h 59m 04s||17d 51m 44s||6.6|
|December 18,2012||04h 57m 60s||17d 53m 04s||6.6|
|December 19,2012||04h 56m 56s||17d 54m 26s||6.6|
|December 20,2012||04h 55m 53s||17d 55m 50s||6.6|
|December 21,2012||04h 54m 51s||17d 57m 17s||6.7|
|December 22,2012||04h 53m 50s||17d 58m 45s||6.7|
|December 23,2012||04h 52m 49s||18d 00m 17s||6.7|
|December 24,2012||04h 51m 50s||18d 01m 50s||6.7|
|December 25,2012||04h 50m 52s||18d 03m 26s||6.7|
|December 26,2012||04h 49m 55s||18d 05m 05s||6.8|
|December 27,2012||04h 48m 59s||18d 06m 46s||6.8|
|December 28,2012||04h 48m 05s||18d 08m 29s||6.8|
|December 29,2012||04h 47m 11s||18d 10m 16s||6.8|
|December 30,2012||04h 46m 19s||18d 12m 04s||6.8|
|December 31,2012||04h 45m 29s||18d 13m 56s||6.9|