Tonight – July 16, 2016 – it won’t be easy to spot the conjunction of the planets Mercury and Venus after sunset. If you want to try it, find an unobstructed western horizon in the direction of setting sun. If you’re blessed with a crystal-clear sky, you might catch these two worlds near the horizon around 30 minutes after sunset.
Shortly thereafter, both Mercury and Venus will follow the sun below the western horizon.
Bring binoculars, if you have them, to increase your chances of spotting these embracing worlds – Mercury and Venus – which reside only one-half degree part on the sky’s dome on this date. For reference, the diameter of the moon spans about one-half degree of sky.
It’ll be much easier to spot the planet Jupiter and star Regulus on these mid-July, 2016 evenings, as shown on the chart at the top of this post.
Jupiter and Regulus will still be out after Mercury and Venus have set. Regulus sinks below the horizon roughly an hour after Venus and Mercury do, and then Jupiter sets approximately one hour after Regulus.
And here’s a sure-fire planet identification for you on the night of July 16. On this night, Mars and Saturn line up with the the waxing gibbous moon:
But back to Venus and Mercury. Day by day, they will climb away from the glare of sunset. Meanwhile, Jupiter and the star Regulus will be falling toward the sunset glare.
Although both Mercury and Venus are moving upward, in the direction of Regulus and Jupiter, Mercury climbs at a swifter pace than Venus. Mercury will meet up with Regulus first, on July 30, 2016. Venus will then stage its rendezvous with Regulus about a week later, on August 5, 2016.
Likewise, Mercury will pair up with Jupiter on August 20, 2016. Then, about a week later, Venus will couple up with Jupiter on August 27, 2016, to present the closest conjunction of two planets for the entire year. Mark your calendar!
By the way, the Southern Hemisphere has the big advantage over the Northern Hemisphere for watching the great race of the inferior planets – Mercury and Venus – in the July and August evening sky.
Bottom line: From around the world on the evening of July 16, 2016, we’re hoping that some of you might spot Mercury and Venus low in the western sky about 30 minutes after sunset. Good luck!
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.