February a great month for sky watchers | ||||
February 1, 2017 | ||||
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By Bruce McClure and Deborah Byrd Earthsky.org Jupiter, the second-brightest planet, lights up the nighttime between late evening 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 around mid-evening. Meanwhile, Saturn appears in the southeastern sky during the predawn hours. Mercury is falling into the glare of the rising sun. 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, and will display its greatest brilliancy as the evening “star” on or near February 17. Be sure to catch the waxing crescent moon near Venus on February 1, and then again on February 28. Venus and Mars remain fairly close together on the sky’s dome throughout February 2017. But brilliant Venus is brightening whereas modestly-bright Mars is dimming. By mid-month, Venus will outshine Mars by over 200 times. When the month of March comes rolling along, Venus will quickly fall downward from Mars, and toward the sunset. Venus will meet up with the setting sun, to transition from the evening to the morning sky, on March 25. Although Mars won’t meet up with the setting sun until late July 2017, Mars will dim all the more between now and then, and moreover, will spend a few months obscured in evening twilight. From mid-northern latitudes (U.S. and Europe), Venus sets about four hours after the sun in early February and about three hours after the sun by the month’s end. At mid-southern latitudes (Australia and South Africa), Venus sets about about two hours after the sun in early February and about one hour after sun by the month’s end. Next month, in March 2017, it may be possible to see Venus as both the evening “star” and morning “star” for a few to several days, starting on or near March 20. Look in the west shortly after sunset to see Venus at dusk, and look east shortly before sunrise to view Venus at dawn. Click here for an almanac giving you the setting time and rising time of Venus in your sky.\ 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, centered on February 1 and again on February 28. 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 2.5 hours after the sun in early February and about two hours after sundown by the month’s end. 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 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 is easy to view in the predawn hours throughout February 2017. From mid-northern latitudes, Saturn rises in the east about three hours before the sun in early February, and by the month’s end, Saturn comes up four hours before sunrise. At temperate latitudes in the Southern Hemisphere, Saturn rises about four hours before the sun in early February, and by the month’s end, Saturn rises around midnight. Be sure to let the waning crescent moon guide you to Saturn (and the nearby star Antares) for several days, centered on or near February 20. 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 27-degrees from edge-on, exhibiting their northern face. In October 2017, the rings will open most widely, displaying a maximum inclination of 27-degrees. 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 27-degrees by May 2032. Seek out the brightest starlike object in the predawn sky or the morning twilight and that’ll be the king planet Jupiter! If you stay up till late evening, you might even catch Jupiter rising above your eastern horizon before your bedtime. From mid-northern latitudes, like those in the U.S. and Europe, Jupiter rises roughly one hour before the midnight hour in early February. By the month’s end, Jupiter rises around 10 p.m. From mid-southern latitudes (Australia), look for Jupiter to rise around mid-to-late evening in early February and early-to-mid evening 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 February 15. 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 three degrees out of perpendicular relative to the ecliptic, 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 three-year period, Callisto will remain “perpetually” visible, alternately swinging “above” and “below” Jupiter. Nominally, Mercury remains in the morning sky all month long, though it also sinks closer to the glare of sunrise daily. From either the Northern Hemisphere or the Southern Hemisphere, your best chance of catching Mercury is during the early part of the month, when Mercury rises a maximum time before sunrise. But Mercury will be better positioned for viewing from the Southern Hemisphere. Watch for Mercury low in the sky, and near the sunrise point on the horizon, seeking for this hidden treasure around 60 to 45 minutes before sunrise. Saturn rises before Mercury does, so use Saturn as your guide “star” to locating Mercury closer to the horizon. Remember, binoculars are always helpful for any Mercury search. Good Luck! Mercury will transition from the morning to evening sky on March 7. For the Northern Hemisphere, Mercury will put on a good showing in the evening sky for several weeks, centered on April 1. 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. In February 2017, two of the five bright planets appear in the evening sky at dusk/nightfall: Venus and Mars. Jupiter is out from late evening till dawn, whereas Saturn and Mercury are found exclusively in the morning sky. |