Two of the five bright planets rise to great prominence in January 2017 sky. Venus rules over the evening sky while Jupiter rules the morning. Venus, the brightest planet, blazes in the west first thing at dusk, and reaches its greatest elongation as the “evening star” on January 12. Jupiter, the second-brightest planet, lords over the eastern half of sky between midnight and sunrise. Mars is near Venus in the evening sky, but it’s higher up and much fainter than Venus, setting in the west shortly after Venus does. Meanwhile, Saturn appears in the southeastern sky before dawn. Mercury a short hop beneath Saturn, just as darkness is giving way to morning twilight. Follow the links below to learn more about planets in January 2017.
Brilliant Venus is the “evening star.” Okay, it’s not a star. It’s a planet. But people will call it the evening star all the same. In these past weeks, many have noticed Venus and been amazed at its brilliance in the west after sunset. It’s the brightest planet and very, very bright, to reach its greatest evening elongation on January 12.
Be sure to catch the waxing crescent moon near Venus in early January, as displayed on the sky chart above. Click here for details.
Watch for Venus to close the gap between itself and Mars. These two visible evening planets will be closer together on the sky’s dome by the month’s end and closer yet in early February 2017.
From mid-northern latitudes (U.S. and Europe), Venus sets about four hours after the sun throughout the month.
At mid-southern latitudes (Australia and South Africa), Venus sets about about three hours after the sun in early January and about 2.5 hours after sun by the month’s end.
Mars, east of Venus, until mid-evening. After appearing as a bright red light in our sky last May and June 2016, Mars now appears only modestly bright (though possibly still ruddy), above dazzling Venus. Venus is so bright that it pops out almost immediately after sunset, but you’ll have to wait until nightfall to see fainter Mars. Look for the moon close to Mars for a few evenings, on or near January 2 or 3.
From mid-northern latitudes (U.S. and Europe), look for the red planet Mars to set in the west around 9 to 10 p.m. all month long.
At mid-southern latitudes (Australia and South Africa), Mars sets in the west around 9 to 10 p.m. (10 to 11 p.m. summer time).
Mars will linger in our sky for several more months. Keep in mind, however, that Earth is traveling away from Mars as we speak – moving far ahead of this planet in the endless race around the sun – so Mars is dimming in our evening sky. Mars is in its long, lingering, relatively inconspicuous phase now. It’ll be still visible in the west to the unaided eye – though not prominent – during its conjunction with Uranus on the evening of February 27, 2017.
Mars won’t make its transition from the evening to morning sky until July 27, 2017. Even so, Mars’ stature in the evening sky will continue to diminish to that of a rather faint “star,” and we expect few – if any – skywatchers to observe the conjunction of Mars and Mercury in the evening sky on June 28, 2017.
The conjunction of Mars and Venus in the morning sky on October 5, 2017, may well present the first good opportunity to spot Mars in the morning sky when it returns from being behind the sun on July 27, 2017.
In both the Northern and Southern Hemispheres, Saturn returned to the morning sky in late December 2016. In early January, Saturn rises in the east about two hours before the sun, and by the month’s end, Saturn comes up several hours before sunrise. Be sure to let the waning crescent moon guide you to Saturn (and the nearby star Antares) for several days, centered on or near January 24.
Saturn, the farthest world that you can easily view with the eye alone, appears golden in color. It shines with a steady light.
Binoculars don’t reveal Saturn’s gorgeous rings, by the way, although binoculars will enhance Saturn’s golden color. To see the rings, you need a small telescope. A telescope will also reveal one or more of Saturn’s many moons, most notably Titan.
Saturn’s rings are inclined at nearly 27o from edge-on, exhibiting their northern face. In October 2017, the rings will open most widely, displaying a maximum inclination of 27o.
As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27o by May 2032.
Bright Jupiter lords over the morning sky. Jupiter’s increasing prominence as the “morning star” will be hard to overlook. To see Jupiter, seek out the brightest starlike object in the predawn sky or the morning twilight and that’ll be the king planet Jupiter! Jupiter rises in the east at late night and soars to its highest point in the sky at or near dawn.
From mid-northern latitudes, like those in the U.S. and Europe, Jupiter rises around one hour after the midnight hour in early January. By the month’s end, Jupiter rises roughly one hour before midnight.
From mid-southern latitudes (Australia), look for Jupiter to rise around midnight in early January and about two hours before midnight by the end of the month.
If you’re not a night owl, your best bet for catching Jupiter is to wake up before sunrise to see this brilliant beauty of a planet lighting up the predawn and dawn sky. Watch for the waning moon to join up with Jupiter for several days, centered on or near January 19. See the above sky chart.
By the way, Jupiter shines in front of the constellation Virgo, near Virgo’s brightest star, Spica. Jupiter serves a great reference for learning the constellations of the zodiac, because Jupiter stays in each constellation for roughly a year. So use Jupiter to become familiar with the star Spica and the constellation Virgo, starting now, and throughout 2017.
If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto.
These moons circle Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we got to view a number of mutual events involving Jupiter’s moons through a high-powered telescope. Click here or here or here for more details.
Although Jupiter’s axial tilt is only 3o out of perpendicular relative to the ecliptic (Earth’s orbital plane), Jupiter’s axis will tilt enough toward the sun and Earth so that the farthest of these four moons, Callisto, will NOT pass in front of Jupiter or behind Jupiter for a period of about three years, starting in late 2016. During this approximate 3-year period, Callisto will remain “perpetually” visible, alternately swinging “above” and “below” Jupiter.
Click here for a Jupiter’s moons almanac, courtesy of Sky & Telescope.
Mercury in the morning sky. Mercury transitioned from the evening to morning sky on December 28, 2016. This month, beginning in the second week of January 2017, Mercury should climb far enough from the glare of sunrise to become visible in the morning sky from both the Northern Hemisphere and the Southern Hemisphere. Saturn rises before Mercury does, so use Saturn as your guide “star” to locating Mercury closer to the horizon.
Try viewing Mercury before sunrise for a few weeks, centered on Mercury’s greatest morning elongation on January 19. Mercury is tricky. If you look too soon, Mercury will be lost in the twilight glare; if you look too late, it will have followed the sun beneath the horizon. Watch for Mercury low in the sky, and near the sunrise point on the horizon, seeking for this hidden treasure around 90 to 60 minutes before sunrise. Remember, binoculars are always helpful for any Mercury search. Good Luck!
For a big challenge, seek for the slender waning crescent moon pairing up with Mercury before sunrise on January 25 and 26. Binoculars may come in handy!
What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.
Bottom line: In January 2017, two of the five bright planets appear in the evening sky at dusk/nightfall: Venus and Mars. The other three planets – Jupiter, Saturn and Mercury – are found in the morning sky.
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.