Venus_Jupiter-June2015.jpg
A conjunction of Jupiter and Venus in June 2015. The encounter between these two planets this week will be the closest they will come until 2065.
(Pmau)
Venus and Jupiter have a close encounter tonight. Venus has been gradually getting higher in the sky, rising to meet Jupiter as the latter sinks down into the west.
This will not be an easy event to view. These planets are very low in the sky. As the sun moves below the horizon at 7:36 p.m., Venus and Jupiter are setting quickly with it. Face due west and start looking for them about 7:45 p.m. A pair of binoculars will help (be careful not to point them at the setting sun). The two planets are only 8 degrees above the western horizon, so you'll need a very clear view in that direction. By 8 p.m., they are only 5 degrees above the horizon.
Venus, Jupiter and Mercury are visible very low in the western sky right after sunset. These three planets are a challenge to see because of their low altitude and bright twilight.
These conjunctions between Venus and Jupiter are not rare, but they can be a visual treat because they are quite bright. During this event, the two planets are extremely close - approximately 5 arc minutes apart. How much is 5 arc minutes? That's a fraction of a degree: 0.08 degrees. Compare this to the full moon's average angular size of 0.5 degrees (31 arc minutes). This is the closest these two planets will be until 2065.
This is much closer than the conjunction last October, when Venus and Jupiter were about 1 degree apart. At their current distance of 5 arc minutes, the two planets will fit easily in the field of view of a telescope. At a magnification of 100x, you should be able to pick out not only Venus but also the four largest moons of Jupiter - strung out all on one side of the planet.
Mercury is also here, but much fainter and lower in the sky. Look for it below and to the left of Venus and Jupiter. With a pair of binoculars, you should be able to fit all three into your field of view.
FIVE PLANETS
With clear weather and a clear view of the western horizon, it may be possible to see all five planets simultaneously.
With Venus, Jupiter and Mercury low in the western sky, and Mars and Saturn in the southwest, all five planets that are visible to the naked eye can be seen. The first three will be quite difficult, but if the weather is clear and you have a good view of the western horizon, you should be able to view all of them in one evening. This doesn't happen very often, though in 2016, we've been lucky to have two opportunities to witness this sight.
Kevin D. Conod is the planetarium manager and astronomer at the Newark Museum's Dreyfuss Planetarium. For updates on the night sky, call the Newark Skyline at (973) 596-6529.