Glimpse the bright asteroid Vesta in February
In mid-February, asteroid 4 Vesta will brighten to magnitude 6.1, making it barely visible to a sharp eye under a dark sky. Astronomy magazine has all the tools you need to get the most of this great observing opportunity.
February 3, 2010
February 3, 2010
Vesta treks through western Leo this month. It slips between 2nd-magnitude Algieba and its 5th-magnitude neighbor, 40 Leonis, the night of February 16/17.
Photo by Astronomy: Roen Kelly
Throughout February, you'll be able to spot asteroid 4 Vesta easily through binoculars and even glimpse it with unaided eyes under a dark sky. The asteroid reaches opposition, and peak visibility, February 17/18. At that point, it will glow at magnitude 6.1.
Vesta orbits the Sun, along with hundreds of thousands of asteroids, in a path lying between Mars and Jupiter. This orbit brings the asteroid opposite the Sun in our sky and closest to Earth February 17/18. During this "opposition," it glows at its brightest for the year. Such events occur roughly every 17 months.
Vesta moves through Leo the Lion during February. Beginning February 1, it forms a rough equilateral triangle with Algieba (Gamma [γ] Leonis) and Eta (η) Leonis. The asteroid moves closer to Algieba during the first half of the month. On the night of February 18/19, Vesta skims between magnitude 2.0 Algieba and magnitude 4.8 southern neighbor 40 Leonis. Just before midnight on February 18, Vesta lies directly between the two stars, one-quarter of the way from Algieba to 40 Leonis. By using these stars as reference points, you can see the asteroid move in just a few hours.
Bright Algieba is a useful guide throughout the month. Asteroid 4 Vesta remains within the same binocular field of view as the star.