The brightest asteroid of them all

D id you know you can see an asteroid using binoculars? This month, look for the brightest asteroid of all, called Vesta, making its way across the night sky. Asteroids are relatively small celestial bodies made up of rock, which mainly orbit the sun in a belt between Mars and Jupiter. Vesta is the second biggest object in this asteroid belt, with a diameter of 525 km. The biggest asteroid by far is Ceres, which has a diameter of 945 km, and in third place is Pallas, diameter 512 km. Although Vesta and Pallas are of similar size, Vesta is made of much denser material and is thus much heavier – it makes up 9 % of the total mass of the asteroid belt! Vesta is also the brightest of all asteroids because its orbit is closer to the sun (and closer to earth). Under ideal conditions, you can even see it with the naked eye. In June, Vesta will move past the Teapot asterism in the Sagittarius constellation. The Teapot will be visible throughout the night for the whole month: It rises in the south-east early in the evening and sets in the west at sunrise. If you don’t know where to find the Teapot, wait until 30 – 31 May or 27 – 28 June – that’s when the moon will be near the Teapot (see illustration). The illustration also indicates Vesta’s position during June in five-day intervals. If you compare the star patterns on consecutive nights, you’ll be able to track Vesta’s progress. Happy hunting!