As Mars approaches Saturn at dusk, Jupiter and Venus are zeroing in on each other at dawn for a spectacular close conjunction Monday morning August 18th. You won’t want to miss this one.
Conjunctions of the two brightest planets occur about once every 13 months but vary in visibility (some happen in daylight) and separation. The closer they get, the more arresting the view.
Tomorrow morning the planets will be a little more than 1º (two full moon diameters apart) – righteously close. But Monday morning they’ll be three times closer, just 0.3º apart or a tad more than a half moon. That’s cozy enough for both to comfortably fit in the same field of view of a telescope.
To watch the event, find a place with a wide-open view to the east as far down to the horizon as possible.
Both planets will about 8º high or just shy of a fist held at arm’s length 40-45 minutes before sunrise.
Bring your camera too! A mobile phone might do OK in twilight, otherwise set your camera’s ISO to 400, place it on a tripod and open the lens to f/4 or 4.5. Then in auto mode, focus your lens at infinity by pointing it at the moon or a cloud. Now click your lens back into manual focus mode and point it at the planets, making a series of exposures from 1 second to 10 seconds. Check the camera back to make sure you’re in the ballpark on both sharpness and exposure.
Close as Jupiter and Venus will be for North America, skywatchers in central Europe will see them even closer (0.2º) before sunrise. After Monday, Jupiter continues its swift rise in the eastern sky while Venus slowly sinks toward the sun. They won’t pair up again until June 30, 2015 when they’ll be just as close in evening twilight in the constellation Leo.
One final and happy note. Not only are the planets pairing up, they also happen to be right next to the Beehive star cluster in the constellation Cancer the Crab. I think you’ll need binoculars to see the cluster clearly, so be sure to have a pair along.
It should be a fun morning. The only down side is that it’s a Monday, meaning you’ll need a nap by the afternoon.