Tonight – July 30, 2016 – the innermost planet Mercury and bright star Regulus in the constellation Leo the Lion present the year’s closest conjunction of a planet and bright star. Their fleeting rendezvous takes place in the glare of evening twilight, unfortunately. Both worlds are bright, but won’t appear bright against a bright twilight background.
If you’re up for the challenge, bring along binoculars to see if you can catch their furtive meeting in the twilight glare.
Find an unobstructed horizon in the direction of setting sun, and in addition, hope for a crystal-clear sky. Some 30 to 40 minutes after sunset, look for the very bright planets Venus and Jupiter to pop out into the western sky. Venus, though the brighter of these two dazzling worlds, might be the harder to spot, because it also sits low in the sky after sunset and near the sunset glare. Once again, binoculars may come in handy.
Seek for the two embracing worlds – Mercury and Regulus – in between Venus and Jupiter, though they’ll be much closer to Venus on the sky’s dome.
The coy couple will slip beneath the horizon about an hour after sunset – or before it gets good and dark – roughly 15 minutes after Venus sinks below the horizon.
Mercury is actually several times brighter than Regulus, the constellation Leo the Lion’s brightest star. So if you see only one starlike object in your binocular field, it’s probably Mercury, the innermost planet of the solar system.
If you miss Venus, Mercury and Regulus, there is still a wonderful consolation prize awaiting you at dusk or nightfall. Jupiter should be easy pickings in the western sky, given that this dazzling world will stay out till after dark.
Also, as darkness falls, look in the south to southwest sky for the planets Mars and Saturn (or look high overhead if you live in the Southern Hemisphere).
If you do spot Mercury and Venus, you may well have the opportunity to view all five bright planets at the same time. These are the planets known and observed by our ancestors since time immemorial: Mercury, Venus, Mars, Jupiter and Saturn.
They’re all in the evening sky, now.
Bottom line: Planet Mercury and star Regulus appear in 2016’s closest conjunction of a planet and a bright star on July 30. Too bad they’re so near the sunset glare.
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.