All five bright planets appear in the April 2017 night sky. Mercury and Mars shine in the west after sunset, while dazzling planet Jupiter – at opposition early in the month – beams in the east, glorious all night long. The two morning planets are Saturn and brilliant Venus. Follow the links below to learn more about the planets in April 2017.
Mercury sets shortly behind the sun. For the Northern Hemisphere, Mercury will put on a good showing in the western evening sky after sunset for several weeks, centered on April 1.
Mercury is tricky. If you look too soon after sunset, Mercury will still be obscured by the haze of evening twilight; if you look too late, it will have followed the sun beneath the horizon. Watch for Mercury low in the sky, and near the sunset point on the horizon, as soon as the sky begins to darken after sunset.
Binoculars are always helpful for any Mercury search. Use them to scan along the western horizon until a starlike point – deep in the twilight – comes into view. Mercury is bright, but it’s always near the sunset or sunrise. Thus you have to search for it.
For the Northern Hemisphere, this particular apparition of Mercury in the evening sky is our best of 2017. From temperate latitudes in the Southern Hemisphere, it’ll be a poor evening showing of Mercury. Just wait, though. A super apparition of Mercury will take place in the morning sky visible from the Southern Hemisphere throughout May of 2017.
Click here for recommended almanacs; they can give you Mercury’s setting time in your sky.
Mars, east of Mercury, until early evening. After appearing as a fiery red light in our sky last May and June 2016, Mars is now a fading ember of its former self. Look for Mars rather low in the west as soon as darkness falls. Mars is edging closer to the sunset day by day. It’ll disappear in the twilight glare in a month or two.
Mars is not the only celestial object to sink into the twilight dusk in April. In fact, you can use Mars to spot the fading Pleiades star cluster, starting on or near April 17. The Zuni of New Mexico called the Pleiades the “Seed Stars” because the cluster’s disappearance from the evening sky signaled that the danger of frost had passed.
From mid-northern latitudes (U.S. and Europe), look for the red planet Mars to set in the west roughly an hour after nightfall in early April and around nightfall by the month’s end.
At mid-southern latitudes (Australia and South Africa), Mars sets at late dusk or nightfall all month long. Mars may be hard to see in the twilight glare from southerly latitudes and binoculars might be needed to spot it.
Let the waxing crescent moon help guide you to Mars on April 27 and 28. Don’t mistake the red star Aldebaran for the red planet Mars, this 1st-magnitude star shining twice as brilliantly as the red planet.
Mars won’t make its official transition from the evening to morning sky until July 27, 2017. It’ll emerge in the east before dawn in September. The conjunction of Mars and Venus on October 5, 2017, might well be the first time most people notice it.
Bright Jupiter opposite the sun in April. Jupiter reaches opposition on April 7 and comes closest to Earth for the year on April 8. Thus, this month, Jupiter shines at its brightest best for all of 2017! It shines all night long – opposite the sun – like a tiny sun from dusk until dawn.
Watch for a full-looking moon to join up with Jupiter for several days, centered on or near April 10, just a few days after Jupiter’s opposition date. See the above sky at the top of this post. Wonderful sight!
From mid-northern latitudes, like those in the U.S. and Europe, Jupiter rises at dusk or nightfall in early April. By the month’s end, Jupiter is seen above the horizon at dusk.
The same applies to tropical latitudes and mid-southern latitudes (Australia). Jupiter rises shortly after sunset in early April and shines above the horizon at dusk in late April.
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, won’t 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.
From mid-northern latitudes, Saturn rises in the east around midnight local time (1 a.m. daylight-saving time) in early April, and by the month’s end, Saturn comes up somewhere around 10 to 11 p.m. local time (11 p.m. to midnight daylight-saving time).
At temperate latitudes in the Southern Hemisphere, Saturn rises about 10 p.m. local time in early April, and by the month’s end, Saturn rises around 8:30 p.m. local time.
But your best view of Saturn, from either the Northern or Southern Hemisphere, is still during the dark hour before dawn. That’s when Saturn climbs highest up for the night. Click here to find out when astronomical twilight starts in your morning sky (remember to click on the astronomical twilight box).
Be sure to let the waning crescent moon guide you to Saturn (and the nearby star Antares) for several days, centered on or near April 16 or 17.
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.
Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.
Venus, brilliant, low in east before sunrise Venus was in the west after sunset. In late March, it entered our morning sky, passing between the sun and Earth on March 25. It’ll reach another period of greatest brilliancy – when it’ll loom low in the east before dawn (likely prompting many “UFO sightings”) before this month ends. That’s because Venus’ greatest illuminated extent as seen from Earth happens on April 30, 2017.
So it’s brightest before dawn this month, but … Venus is always bright, the brightest thing in our sky besides the sun and moon. If you’re an early bird, you can count on Venus to be your morning companion for many months to come.
Enjoy the picturesque coupling of the waning crescent moon and Venus in the eastern sky before sunrise on or near April 23.
From mid-northern latitudes (U.S. and Europe), Venus rises about one hour before the sun in early April and nearly two hours before sunrise by the month’s end.
At mid-southern latitudes (Australia and South Africa), Venus rises about about one hour before the sun in early April and 3 hours before sunup by the month’s end.
Click here for an almanac giving rising time of Venus in your sky.
The chart below helps to illustrate why we sometimes see Venus in the evening, and sometimes before dawn.
Since Venus passed 8o north of the sun on March 25, it was possible to see Venus as both the evening and morning “star” for several days at northerly latitudes. That’s because, at northerly latitudes, far-northern Venus set after the sun and then came up before the sun as this inferior planet moved over to the morning sky. How often does that happen? It recurs in cycles of 8 years. We’ll see Venus as both a morning and evening sky again – for a few days – when Venus reaches its 5th inferior conjunction in 8 years on March 23, 2025. It’ll happen again when Venus reaches its 10th inferior conjunction in 16 years on March 20, 2033.
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 April 2017, three of the five bright planets appear in the evening sky: Mars, Jupiter and Mercury. Saturn and Venus are found 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.