For the Northern Hemisphere, mid-March 2012 presents the best time to see a Venus-Jupiter conjunction in the evening for years to come. At mid-northern latitudes, these two brightest planets – Venus and Jupiter – stay out for nearly four hours after sunset. That’s about the longest period possible at these latitudes. You can’t miss these two worlds in the west as darkness falls.
And in the opposite direction at nightfall – looking east – you can’t miss the ruddy planet Mars. This world won’t be so brilliant in our sky again until April 2014. Mars shines from dusk till dawn, whereas Venus and Mars set four hours after sunset at mid-northern latitudes.
March 15, 2012 presents the exact date of conjunction, when these two worlds have the same right ascension (like longitude on Earth) in Earth’s sky. But Venus and Jupiter are close throughout the month of March 2012. They are like twin beacons – two very bright planets – near each other in the west as soon as the sun goes down.
The next Venus-Jupiter conjunction after this one falls on May 28, 2013. Although Venus and Jupiter will be closer together on the sky’s dome during that conjunction, they won’t be as spectacular then as they are this month. That’s because, in May 2013, the two planets will set only a little more than one hour after the sun (at mid-northern latitudes).
Why are Venus and Jupiter up so long after sunset now? For any Venus-Jupiter conjunction to light up the nighttime for a maximum time after dark, a perfect storm of conditions has to prevail. First of all, Venus has to be at or near its greatest evening elongation – farthest angular distance from the setting sun. Second, the ecliptic – or pathway of the planets – has to make its steepest angle with the sunset horizon. Both of these conditions exist this month. The greatest elongation for Venus – when this planet is due to be farthest from the sunset – will happen on March 27, 2012. As for the angle of the ecliptic, it could not be more ideal than March for evening viewing, as seen from the Northern Hemisphere.
The close coincidence of Venus and Jupiter in conjunction, the steep angle of the ecliptic and Venus’ greatest evening elongation keeps these worlds up for several hours after dark – and ensures the Northern Hemisphere of a beautiful gathering of worlds in the western evening sky this month. They are well worth getting outside to see.
Bottom line: Venus and Jupiter are in conjunction on March 15, 2012. This is the best evening Venus-Jupiter conjunction for years, as seen from the Northern Hemisphere. Venus and Jupiter stay out for nearly four hours after sunset. Venus and Jupiter are close throughout the month of March 2012. They are like twin beacons – two very bright planets – near each other in the west as soon as the sun goes down.