May 24, 2013
Spectacular Triple Conjunction This Weekend
[ Watch the Video: ScienceCasts: Sunset Triangle ]
John P. Millis, Ph.D. for redOrbit.com — Your Universe OnlineFans of stargazing are in for a treat this weekend. Over the next several days the planets, Venus, Jupiter, and Mercury will approach each other in the fading sunlight to form a triple conjunction — where three bodies appear to converge in the sky.
The events will culminate on the evening of the 26th, and will appear to form a triangle just above the horizon. The best time to see it will be about 30 — 60 minutes after the Sun sets below the horizon, while the orange glow still hangs in the sky.
The easiest of the planets to see is Venus, as it is very bright, visible even before the Sun is completely set. If you can identify that planet first, then its companions should be relatively easy to pick out, as they emerge from darkness once the Sun´s light fades.
The three worlds will appear in a region of the sky less than three degrees apart. (For comparison the Moon is about half a degree in diameter.) You don´t have to wait until Sunday to see the planets approaching, as they have already begun their trek, so be on the lookout each sunset and watch them converge.
On the 27th the planets will begin to move apart from their tightest compactness, but Venus and Jupiter will continue to approach each other and on the evening of the 28th, the two will pass within one degree of each other.
This is the first such conjunction since May 2011, and won´t occur again until October 2015. So if you are a fan of stargazing, this will be your last chance for a while.