How to Spot Venus and Jupiter

Venus (on the left) and Jupiter in the evening sky in 2008.
 This week their positions will be reversed.  

After the moon, they are the two brightest objects in the night sky, and for the next few evenings they will appear side-by-side in western skies in a dazzling heavenly spectacle.

Though Jupiter is seven times farther from Earth than Venus, the planets' orbits bring them into close approach on Tuesday evening, when they will appear only three degrees, or a few finger-widths, apart.

From Tuesday, the planets will gradually move apart, but remain within five degrees of one another until Saturday, after which their next heavenly meeting in fully dark skies will be on June 2015. Venus, the second rock from the sun, appears by far the brighter of the two, because it receives and reflects more intense sunlight than reaches Jupiter, the fifth planet out, beyond the orbit of Mars.

With binoculars or an amateur telescope, stargazers might glimpse three or four moons in orbit around Jupiter. Observations of these moons 400 years ago prompted Galileo to declare that not all heavenly bodies orbited the Earth.

All of the planets in the solar system orbit the sun in more or less the same plane, so they appear on a line in the sky called the ecliptic. Draw a line through Jupiter and Venus and it will eventually lead to the reddish dot of Mars, and later Saturn, in the eastern night sky.

18th March 2012