Follow the links below to learn more about the planets in April 2018:
Mars and Saturn rise into the southeast sky quite late at night throughout April (especially as viewed from the Northern Hemisphere). Your best view of them is just before dawn, when these planets appear much higher up in the sky, as seen from around the world. You can tell Mars from Saturn because Mars has a reddish color. Saturn looks golden in color. Binoculars show their colors better than the eye alone.
These two stage a close planetary conjunction on April 2. They remain in the same binocular field throughout the first week of April. Use the waning gibbous moon to find Mars and Saturn on April 7 (see sky chart above). As seen from North America on April 7, all three worlds – the moon, Mars and Saturn – fit (or nearly fit) inside a single binocular field of view.
Mars and Saturn are now shining in front of the constellation Sagittarius, not far from the direction to our galaxy’s center. After their April 2 conjunction, as the month progresses, Mars will travel east of Saturn to move out of the constellation Sagittarius and into the constellation Capricornus by mid-May 2018. Saturn, in the meantime, will stay in front of the constellation Sagittarius for several more years.
At present, both Mars and Saturn easily shine as brilliantly as 1st-magnitude stars. However, Mars is slightly brighter than Saturn. Saturn’s brilliance will increase until it peaks at its June 27 opposition, and Mars’ brilliance will also increase until it peaks at its July 27 opposition.
But Saturn’s brightness increase will be subtle, while Mars’ will be dramatic! It’s not often that Mars outshines Jupiter, normally the fourth-brightest celestial object to light up the sky, after the sun, moon and Venus, respectively. But Mars will actually outshine Jupiter for a couple of months in 2018, centered on Mars’ July 27 opposition. Remember Mars’ historically close opposition of August 28, 2003? That year, it was closer and brighter than it had been in some 60,000 years. This upcoming July opposition will be the best since then.
Jupiter is always hard to miss. In April 2018, it’s the fourth-brightest sky object, after the sun, moon and Venus. Look southeast before your bedtime, and if you see a starlike object near the horizon that’s brighter than any star, that’s probably Jupiter. On April 2 and 3, watch for the waning gibbous moon near Jupiter (see sky chart above). Or get up before sunrise to see the moon and Jupiter on the mornings of April 3 and 4. Look for the moon to meet up with Jupiter again, on April 30.
In early April, at mid-northern latitudes (U.S., Europe, Japan), Jupiter comes up at roughly 10 p.m. (11 p.m. daylight saving time). At temperate latitudes in the Southern Hemisphere (South Africa, southern Australia and New Zealand), Jupiter will be up around 9 p.m. in early April. After Jupiter rises, it’s out for the rest of the night.
By late April, as seen from around the world, Jupiter will climb into the evening sky about an hour after sunset. Around its opposition on May 9, 2018 – when Earth flies between Jupiter and the sun, gaining a lap on the planet for this year – Jupiter will be rising in the east as the sun sets in the west, out all night, from dusk until dawn.
It’ll be fun to watch Jupiter and Venus from mid-April on, when Venus will set in the west as Jupiter is rising in the east (assuming a level horizon). By the month’s end, you should easily see the sky’s two brightest planets – Venus in the west, and Jupiter in the east – as night descends.
Jupiter shines in front of the constellation Libra the Scales until November 2018 (see sky chart above). Look for Libra’s brightest stars near Jupiter, Zubenelgenubi and Zubeneschamali (both star names are pronounced with the same rhythm as Obi-Wan Kenobi, of Star Wars). If you aim binoculars at Zubenelgenubi, you’ll see this star as two stars. Zubeneschamali, meanwhile, is said to appear green in color, although, astronomers say, stars can’t look green.
Venus is the brightest planet. It just returned to the evening sky in February, and, throughout April, Venus appears as a dazzling evening “star,” found in the west after sunset. This month, the planet is still climbing upward from the sunset point. Each evening in April, it stays out longer after the sun sets. Venus will remain a fixture our evening skies until October 2018.
Circle April 17 on your calendar. That’s when the young moon swings to the south of Venus for a picturesque pairing in the western twilight (see the sky chart above).
At mid-northern latitudes (U.S., Europe, Japan), Venus sets about 1 1/2 hours after the sun at the beginning of April, and by the month’s end, sets about two hours after sunset. From temperate latitudes in the Southern Hemisphere (South Africa, southern Australia, New Zealand), Venus sets about one hour after the sun in early April, and by the month’s end, sets about 1 1/2 hours after sunset. Click here for recommended sky almanacs; they can give you Venus’ setting time in your sky.
Mercury, the innermost planet of the solar system, sweeps to inferior conjunction on April 1, 2018, thereby transitioning out of the evening sky and into the morning sky. The upcoming morning apparition of Mercury in April and May 2018 will be the best of the year for the Southern Hemisphere, but poorest of the year for the Northern Hemisphere.
Around mid-April 2018, Mercury should be far enough west of the sun to become visible in the east before sunrise at southerly latitudes. Watch for the waning crescent moon to swing into the vicinity of Mercury on April 13 and 14.
Mercury will reach its greatest western elongation from the sun on April 29, 2018. At temperate latitudes in the Southern Hemisphere (South Africa, southern Australia, New Zealand), Mercury will rise more than two hours before the sun. But at mid-northern latitudes (United States, Europe, Japan), Mercury will come up only about one hour before sunrise.
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 2018, Venus appears in the west in evening twilight, Jupiter rises at mid-to-late evening and is well up by dawn. Mars and Saturn rise late at night and are also well up by dawn. Mercury makes an appearance in the east before sunrise in the latter half of April (at southerly latitudes). Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your 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.