Protoplanet 4 Vesta Reaches Opposition August 5

Asteroid (and protoplanet) 4 Vesta reaches opposition August 5, and should be a great target for observers the next few weeks. Tonight, Vesta will shine around magnitude 5.63 (bright); to learn more about observing Vesta, come to our minor-planets viewing page, courtesy of Sky&Telescope, in the section entitled "Viewing 1 Ceres and 4 Vesta through the rest of 2011."

...The two brightest and most massive objects in the asteroid belt come alive in the night sky: just for you to view. Currently in 2011, Vesta (which is now being visited by Dawn) is in Capricornus, continuing it's 3.6 year orbit in the asteroid belt. Ceres, on the other hand, takes longer to orbit at 4.6 years and is about 1 and one half constellations to the east, on the Aquarius/Cetus borderline. 2012 brings these objects into Taurus, where Mars sits now (July 20).

To view these asteroids, Vesta will be up all night (especially around 3 am local time); but both objects will be in best view at opposition. Opposition is appropriately when an object is the highest in the night sky, as viewed from your position on earth. Vesta is in opposition August 6, and Ceres, September the 16th. Here is a good magnitude list to show you the magnitude of the object on a certain date...

Vesta will be viewed in the constellation Capricornus

This year, Vesta will be the brightest minor-planet (asteroid, protoplanet, etc - whichever you wish to call it) visible to us. "The best Ceres will manage this year is magnitude 7.6 and Pluto a meagre magnitude 14.3," write the Loughton Astronomical Society. Being at opposition is a fairly major astronomical event, but can opposition be defined? In the astronomical sense, opposition is "the position of an outer planet (or asteroid) when it is in line...with the earth as seen from the sun and is approximately at its nearest to the earth," Collins English Dictionary defines. Our chart shows this example.

Vesta will be best seen around midnight, but it reaches opposition at 10:25:57 UT, which was respectively 6:25:57 this morning (August 5). Vesta's magnitude is still going strong though!

Want a glimpse of Dawn? Learn more here...