A Visit to Vesta
July 2011 :
Note: This article may contain outdated information
This article was published in the July 2011 issue of The Skyscraper and likely contains some information that was pertinent only for that month. It is being provided here for historical reference only.
On July 16, NASA’s Dawn spacecraft will enter into orbit around Vesta, one of the largest asteroids in the asteroid belt between Mars and Jupiter. The ion-propulsion spacecraft will spend a year observing Vesta with its three on-board instruments before breaking orbit and traveling on to dwarf planet Ceres, the largest of the main-belt asteroids and the first minor planet discovered.
Due to a favorable combination of distance from Earth, large size, and highly reflective surface, Vesta is most often the brightest asteroid in the sky. Near opposition is can even outshine Uranus and become naked-eye visible under a dark sky.
July 2011 presents an opportunity to spot Vesta as it loops through eastern Capricornus on its way to opposition on August 5. Its motion with respect to the background stars will be readily apparent on successive nights through binoculars. Through a telescope at moderate power you should be able to detect its starlike appearance moving over the course of an hour.
The chart shows the position of Vesta at 1:20 am EDT on 5-day intervals through July and the shaded line marks the approximate path it follows between the marked dates. The asteroid will brighten from magnitude 6.3 to 5.7 as its distance from Earth closes from 1.34 to 1.23 AU.
