Brilliant Venus in west at nightfall. Venus – brightest of all planets, and third-brightest object in the sky after the sun and moon – sits in the glare of evening twilight for for the most of January, 2015. A fainter world would not show up in such bright twilight, but Venus is very bright! Many have already captured its photo. Also, use Venus this month to find the planet Mercury nearby.
In early January, Venus sets about 75 minutes after sunset at mid-northern latitudes. Its visibility improves throughout January, and this dazzling world sets nearly two hours after the sun by the month’s end.
Be sure to watch the skies on January 21, January 22 and January 23, when the waxing crescent moon will be back in the evening sky, moving up past first Venus and then Mars in the western twilight. Find an unobstructed horizon in the direction of sunset, and bring along binoculars, if you have them, to enhance the view.
Mercury below Venus at nightfall. Mercury is our solar system’s innermost planet and always stays near the sun in our sky. However, January presents a grand month for catching Mercury in the evening sky for the Northern Hemisphere.
At mid-northern latitudes, this world sets about one hour after sun in early January. Some two weeks later – on January 14 – Mercury will reach reach its greatest elongation from the sun, to set a whopping one and one-half hours after sunset.
Mercury might – or might not – become visible to you in your evening sky in early January, when it sets about one hour after the sun. To see it, you’ll need a clear sky and an unobstructed horizon. It’ll be lots of fun to see, though, near Venus shortly after sunset. Your binoculars will help you scan for Mercury in the bright evening twilight. Have fun looking! And when you find it … what a special treat.
Be sure to circle January 10 on your calendar. That’s when Mercury and Venus will showcase their closest coupling on the sky’s dome until May 25, 2016!
Mars visible in sunset direction from nightfall until mid-evening. Mars reliably pops into view as soon as darkness falls throughout January, 2015. It is rather low in the southwestern twilight sky now. Catch the red planet at nightfall because this world sets rather early in the evening throughout January.
The red planet Mars is getting dimmer as it lags behind us in its larger and slower orbit, but is nonetheless visible to the unaided eye in a dark sky. This ruddy world still shines pretty much on par with a 1st-magnitude star, though the evening twilight obscures this planet’s luster. Mars starts the month in the constellation Capricornus and then enters the constellation Aquarius during the second week of January 2015.
At mid-northern latitudes, Mars sets about 3 hours after the sun nearly all month long. But like a fading ember, this world is slowly but surely disappearing into the glow of sunset as Earth races ahead of it in orbit.
Bright Jupiter from mid-evening until dawn all month. Jupiter – the second-brightest planet after Venus – rises in the east at roughly 8 p.m. in early January and 6 p.m. by the end of the month. But Venus sets at early evening, so Jupiter lords over the nighttime from mid-evening till dawn.
Once Jupiter rises over the eastern horizon, it’s unmistakable. This world shines more brilliantly than any star.
Be sure to watch for Jupiter adorning the eastern sky on these January 2015 evenings. Earth is speeding toward Jupiter, so Jupiter will continually rise earlier and earlier in the evening all month long. Earth, in its smaller and speedier orbit around the sun, will catch up with Jupiter on February 6, 2015. At that juncture, Jupiter will be out all night long, shining from sundown to sunup.
If you have binoculars or a telescope, be sure to check out 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.
Click here for a Jupiter’s moons almanac, courtesy of Sky & Telescope.
Saturn visible in January’s eastern predawn sky. Saturn reappeared in the morning sky in December, 2014. At mid-northern latitudes, Saturn rises about three hours before sunup in early January and some three and one-half hours before the sun by the month’s end. Watch for the waning crescent moon to couple up with Saturn for several mornings mornings, centered on January 16.
Binoculars don’t reveal Saturn’s gorgeous rings. For that, you need a small telescope. Early December will probably present your first opportunity to view Saturn in the morning sky, and the planet might become a decent telescopic object by late December, assuming you’re an early riser.
Saturn’s rings are inclined at about 25o from edge-on in January 2015, exhibiting their northern face. Several years from now, 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.
What do we mean by visible planet? By visible 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 visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.
Bottom line: In January 2015 Venus and Mercury come out briefly after sunset; Mars lights up the early evening hours; Jupiter is out from mid-evening until dawn; and Saturn is found in the predawn/dawn sky. All five visible planets can be seen in January!