Tonight – August 4, 2016 – we give you fair warning. It won’t be easy to catch the thin waxing crescent moon pairing up with the planet Mercury in the western twilight some 45 to 60 minutes after sunset on August 4. Bring along binoculars, if you have them, and find an unobstructed horizon in the direction of sunset. Better yet, stand atop a hill or balcony, which will enable you to see that much farther over your western horizon.
Our chart above shows the sky scene as viewed from mid-northern latitudes in North America. From mid-northern latitudes in Europe and Asia, the planets will be similarly positioned in the western sky, yet the moon will be offset in the direction of Venus.
From the Southern Hemisphere, as anywhere worldwide, look in your western sky after sunset for the moon and planets. But, from the northern tropics and the Southern Hemisphere, be mindful that the line-up from top to bottom – Jupiter, Mercury and Venus – will be closer to perpendicular to the horizon, as illustrated in the chart below.
From around the world after sunset, the moon and Mercury, the solar system’s innermost planet, shine in between the sky’s brightest and second-brightest planets: Venus and Jupiter, respectively.
Venus, the second planet outward from the sun, lurks beneath the moon and Mercury, on the sky’s dome.
Meanwhile, Jupiter, the fifth planet outward, sits above the moon and Mercury.
Although Venus is the lowest planet in the sky, and is the first planet to set after sunset, this world ranks as the third-brightest celestial body, after the sun and moon. With binoculars or the unaided eye, you may be able to spot Venus as early as 30 minutes or less after sunset. Click here to find out when Venus sets in your sky. If you spot the moon before you see anything else after sunset, remember that the lit side of the moon points in the general direction of Venus. Binoculars could come in handy for sighting Venus, Mercury and a zoomed-in view of earthshine on the moon.
If you miss the moon, Venus, Mercury and Jupiter after sunset on August 4, you can still use the moon to help you find these worlds over the next several days. As dusk deepens into darkness tomorrow – on August 5 – look for the moon to have moved in the direction of Jupiter.
Assuming you have clear skies, it’ll be possible to catch all five naked-eye planets by nightfall. In their order going outward from the sun, these five planets are Mercury, Venus, Mars, Jupiter and Saturn.
It’ll be considerably easier to spot Mars and Saturn, because they’ll be out until midnight at mid-northern latitudes and well past midnight at more southerly latitudes. At mid-northern latitudes, as darkness falls, look southward to spot Mars and Saturn near Antares, the brightest star in the constellation Scorpius the Scorpion. From the Southern Hemisphere, look high overhead as darkness falls for Mars and Saturn.
Bottom line: On August 4, 2016, at dusk and nightfall, use the moon to locate Mercury in the western sky, and go on from there to spot all five bright planets.