Hot on the heels of last months’ arrival of NASA’s spacecraft Dawn at asteroid Vesta, backyard skywatchers throughout August get a chance to see the space rock for themselves in its best and brightest apparition until 2018.
After a four year journey Dawn entered orbit around the 500 km wide asteroid in mid July and will remain at Vesta for a year. Circling the Sun between the orbits of Mars and Jupiter in the main asteroid belt, Vesta is the second largest asteroid known with an ancient battered surface that may hold clues to how the planets formed 4.5 billion years ago.
While Dawn is getting up close and personal, for us Earthlings Vesta looks like a very faint star-like object in in a sea of stars, visible to the naked eye but only from a dark location – like cottage country. For those stuck under light polluted city skies I recommend a pair of binoculars or small telescope.
Vesta officially reaches opposition – opposite in the sky from the Sun, – on August 5 and will be at its brightest at magnitude 5.6 around that date- the most brilliant any asteroid can technically ever get in our skies.
Throughout August Vesta will be flying through the chevron-shaped constellation Capricornus, located towards the southern horizon during late nights. While you can easily track the asteroid down with binoculars, a telescope will allow you to watch it move in front of a background of stars. In fact it’s zipping along at such a quick pace you should be able to detect its movement through a medium power eyepiece over the course of a single night.
With a help of these star charts above, a steadily held binoculars, and some patience you should be able to find 380 million km distant Vesta. Sky and Telescope website also has some printable skycharts (PDF) too.
While it certainly isn’t much to look at, your reward is simply being able to hunt it down for yourself from your backyard, while knowing that we humans currently have our robotic explorer circling this distant worldlet.