Night Sky, April 2019: What You Can See This Month [Maps]

The night sky tonight and on any clear night offers an ever-changing display of fascinating objects you can see, from stars and constellations to bright planets, often the moon, and sometimes special events like meteor showers. Observing the night sky can be done with no special equipment, although a sky map can be very useful, and a good beginner telescope or binoculars will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy accessories to make your observing easier, and use our Satellite Tracker page powered by N2YO.com to find out when to see the International Space Station and other satellites. Below, find out what's up in the night sky tonight (Planets Visible Now, Moon Phases, Observing Highlights This Month) plus other resources (Skywatching Terms, Night Sky Observing Tips and Further Reading).

The night sky is more than just the moon and stars, if you know when and where to look.
(Image: © Karl Tate/SPACE.com)

Monthly skywatching information is provided to Space.com by Chris Vaughan of Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu.

Editor's note: If you have an amazing skywatching photo you'd like to share for a possible story or image gallery, you can send images and comments in to spacephotos@futurenet.com.

Yearly Night Sky Guides:

When, Where and How to See the Planets in the 2019 Night Sky

The Top Skywatching Events to Look for in 2019

Best Night Sky Events of March's 2019 (Stargazing Maps) 

Calendar of Observing Highlights

 Monday, April 1 evening – Red Mars near the Blue Pleiades

In the western evening sky on the evenings around Monday, April 1, Mars' eastward orbital motion (orange line) will carry it three finger widths to the left of the bright open star cluster known as the Pleiades, the Seven Sisters, and Messier 45. For best results, view the pairing in binoculars (red circle) while they are higher in the sky — before about 9 p.m. local time.

Monday, April 1 from 11:52 to 12:58 GMT — Double Shadow Transit on Jupiter

From time to time, the small round black shadows cast by Jupiter's four Galilean moons become visible in amateur telescopes as they cross (or transit) the planet's disk. On Monday, April 1, observers in the western Americas and the Pacific Ocean region can see two of those shadows on Jupiter at the same time. At 11:52 GMT, Ganymede's shadow will join Europa's shadow already in transit. The two shadows will cross Jupiter's northern hemisphere together for 66 minutes until Europa's shadow moves off the planet at 12:58 GMT. Ganymede's shadow will continue to transit Jupiter for another hour.

Tuesday, April 2 pre-dawn — Old Moon Meets Mercury and Venus

Low in the east-southeastern sky before sunrise on Tuesday, April 2, the very old crescent moon will be visible sitting four degrees below bright Venus. The pair will fit within the field of view of binoculars (orange circle). A tricky-to-see extra bonus will be much dimmer Mercury sitting 8 degrees to the moon's left — and distant Neptune half of a degree below Mercury!

Friday, April 5 at 8:50 GMT — New Moon

At its new phase, the moon is traveling between the Earth and the Sun. Since sunlight is only reaching the side of the moon pointed away from us, and the moon is in the same region of the sky as the sun, the moon is hidden from view for Earth-bound observers. A day or two after new moon, look for the slender sliver of the young crescent moon just above the western horizon after sunset. 

Monday, April 8 after midnight — Ceres Stands Still

On Monday, April 8, the dwarf planet Ceres, named for the Greek goddess of agriculture, will cease its eastward motion through the distant stars (red curve with dates) and commence a westward retrograde loop that will last until mid-July. Ceres' visual magnitude of 8.0 will allow it to be seen in binoculars and amateur telescopes in the southern sky between about 1 a.m. local time and the dawn twilight. The asteroid's position on April 8 will be among the stars of southern Ophiuchus, approximately 11 degrees to the upper left (northeast) of the bright star Antares in Scorpius. 

Monday, April 8 evening – Crescent Moon Passes Mars

In the western sky on the evening of Monday, April 8, the waxing crescent moon will land 7 degrees below reddish Mars. On the following evening, the moon's orbital motion will place 9 degrees to Mars' upper left. At the same time, look for the bright, orange star Aldebaran sitting 7 degrees to the left of Mars and the bright little Pleiades Cluster a palm's width to the lower right of Mars.

Wednesday, April 10 all night — Pallas at Opposition near Murphrid

On Wednesday, April 10, the main belt asteroid designated (2) Pallas will reach opposition, its closest approach to Earth for the year. On the nights around opposition, Pallas will shine with a peak visual magnitude of 7.9, well within reach of binoculars. As a bonus, the asteroid will be situated only 0.25 degrees (half the full moon's apparent diameter) to the lower left of the bright double star Murphrid, which is also designated as Eta Boötis (η Boötis). They will easily fit within the field of view of a backyard telescope. (Your telescope will mirror and/or invert the inset view shown). The asteroid and star will already be climbing the eastern sky after dusk and will spend the night crossing the sky together. 

Wednesday, April 10 after midnight — Jupiter Reverses Direction

For most of this year, the bright planet Jupiter will travel within the constellation of Ophiuchus, the Serpent-Bearer. On Wednesday, April 10, Jupiter will cease its regular eastward motion in front of the distant stars and begin a retrograde loop (red curve with dates) that will last until early August. The apparent reversal in Jupiter's motion is an effect of parallax produced when Earth, on a faster orbit, passes Jupiter on the "inside track."

Thursday, April 11 pre-dawn — Mercury at Greatest Western Elongation

On Thursday, April 11, Mercury (orbit shown as a red curve) will reach its widest separation 28 degrees west of the Sun. Due to Mercury's position well below a slanted morning ecliptic (green line), this will be a very poor pre-dawn apparition for Northern Hemisphere skywatchers, but a very good one for those viewing the planet from the Southern Hemisphere. 

Friday, April 12 at 19:07 GMT — First Quarter Moon

At first quarter, the relative positions of the Earth, sun, and moon cause us to see the moon half illuminated — on the eastern (right-hand) side. First quarter moons rise around noon and set around midnight, so they are visible starting in the afternoon hours. The term quarter moon refers not to its appearance, but the fact that our natural satellite has now completed the first quarter of its orbit around Earth since the last new moon. 

Saturday, April 13 evening — Moon Buzzes the Beehive

In the southwestern sky after dusk on Saturday, April 13, the waxing gibbous moon will be positioned a few degrees to the left of the large open star cluster in Cancer known as the Beehive, Praesepe, and Messier 44. Binoculars will encompass both the moon and the cluster in the same field of view (orange circle), but to see the clusters' stars, position the moon just outside of your binoculars' field of view. A few hours earlier, at approximately 19:30 GMT, observers in Western Europe, the Middle East, and eastern Africa can see the moon's orbit (green line) carry it directly through the cluster. 

Friday, April 19 at 11:13 GMT — Full Pink Moon

The April full moon, known as the Pink Moon, Sprouting Grass Moon, Egg Moon, or Fish Moon, always shines in or near the stars of Virgo. Full moons always rise in the east as the sun sets, and set in the west at sunrise. When fully illuminated, the moon's geology is enhanced, especially the contrast between the ancient cratered highlands and the younger, smoother maria. This year we celebrate the 50th anniversary of the first footsteps by humans on the moon. 

Monday, April 22 – pre-dawn — Lyrids Meteor Shower Peaks

The annual Lyrids meteor shower, derived from particles dropped by comet C/1861 G1 (Thatcher), runs from April 16 to 28 and peaks before dawn on Monday, April 22. The meteors will streak away from a point in the sky (the shower's radiant) near the bright star Vega, which will be high in the eastern sky before dawn. The Lyrids can produce up to 18 meteors per hour, with occasional fireballs. Unfortunately, a bright, gibbous moon will wash out all but the brightest meteors this year. 

Tuesday, April 23 wee hours to dawn – Moon near Jupiter

When the bright planet Jupiter rises in the southeastern sky at about 12:15 a.m. local time on Tuesday morning, April 23, it will be positioned 3 degrees to the lower left of the waning gibbous moon. The moon and planet will cross the sky together for the rest of the night, eventually moving to a point low in the southwestern pre-dawn sky. The duo will make a lovely photo opportunity when composed with an interesting foreground landscape. 

Thursday, April 25 pre-dawn – Moon Meets Saturn

In the southeastern pre-dawn sky on Thursday, April 25, the last quarter moon will land less than 3 degrees to the right of yellowish Saturn, near the Teapot-shaped stars of Sagittarius. The duo will fit nicely into the field of view of binoculars (orange circle), and make a nice photograph. Half a day later, at 13:00 GMT, observers in Eastern Australia and New Zealand will see the moon occult Saturn. 

Friday, April 26 at 22:19 GMT — Last Quarter Moon

At its last quarter phase, the moon rises around midnight and remains visible in the southern sky during morning daylight. At this time, the moon is illuminated on the western (left-hand) side, towards the pre-dawn Sun. Last quarter moons are positioned ahead of the Earth in our trip around the Sun. About 3½ hours later, earth will occupy that same location in space. After this phase, the waning moon traverses the last quarter of its orbit around the earth, on the way to new moon. 

Monday, April 29 pre-dawn – Saturn Stands Still

On Monday, April 29, Saturn will temporarily cease its regular eastward motion in front of the distant stars of Sagittarius and begin a retrograde loop (red curve with dates) that will last until mid-September. The apparent reversal in Saturn's motion is an effect of parallax produced when Earth, on a faster orbit, passes the Ringed Planet on the "inside track."

Planets

Mercury will spend April in the eastern pre-dawn sky. Due to the planet's position below a tilted morning ecliptic, this will be a very poor pre-dawn apparition for Northern Hemisphere skywatchers, but a very good one for those viewing the planet from the Southern Hemisphere. During the month, Mercury will shrink in apparent diameter and increase in brightness while waxing from a 30 percent illuminated crescent to a gibbous phase. On April 3, Mercury will pass 0.3 degrees north of Neptune, but that distant blue planet will be invisible within the morning twilight. On the mornings surrounding April 16, Venus will approach to within 5 degrees of Mercury. On April 11, Mercury will reach its widest separation 28 degrees west of the Sun.

Venus will spend April sitting low in the eastern pre-dawn sky while it swings sunward. Venus will move from Aquarius into Pisces on April 17. Throughout the month, Venus' extremely bright visual magnitude of -3.9 will allow it to be seen within the dawn twilight, especially around 6 a.m. local time. Meanwhile, the planet will shrink slightly in apparent disk diameter, and wax from 82 percent to 88 percent illuminated. On April 1, the old crescent moon will appear 9 degrees to the right of Venus. On April 10, Venus will sit 0.3 degrees south of dim Neptune. On the mornings surrounding April 16, Venus will approach to within 5 degrees of Mercury.

Mars will spend April in the western evening sky, moving eastward among the stars of Taurus. It will remain a target for early evening observing while the planet slowly descends towards the western twilight. Meanwhile, Earth's orbital motion will continue to increase our distance from the Red Planet, causing Mars to dim from visual magnitude 1.45 to 1.63. Mars' apparent disk diameter will decrease slightly in size at the same time. The planet will spend the first days of April sitting several degrees to the left (south) of the bright open star cluster known as the Pleiades (or Messier 45). On April 9, the waxing crescent moon will land 7 degrees below (southwest of) Mars. On the following evening, the moon's orbital motion will take it 9 degrees to Mars' upper left.

Very bright Jupiter will be a pre-dawn target until April 27, at which time it will officially become observable before midnight local time. The planet will be located in southern Ophiuchus all month, slowly moving eastward until April 10, when it will begin a westward retrograde loop that will last until early August. During the month, Jupiter will brighten slightly from visual magnitude -2.25 to -2.45 and grow in apparent disk diameter from 39.9 to 43.4 arc-seconds as we head toward its June opposition date. On April 23, the planet will be positioned 3 degrees to the lower left of the waning gibbous moon.

Saturn will be easily observable in the southeastern pre-dawn sky during April, appearing as a yellowish object located 7 degrees east of the handle of the Teapot asterism that forms Sagittarius. On April 29, Saturn will temporarily cease its regular eastward motion and begin a retrograde loop that will last until mid-September. On April 25, the last quarter moon will land less than 3 degrees to the right of yellowish Saturn. Over the course of April, Saturn will brighten slightly from magnitude 0.57 to 0.46, and will rise steadily earlier in preparation for becoming an evening object next month.

Except for the first few evenings of April, blue-green Uranus, in Aries, will not be observable this month. It reaches conjunction with the sun on April 22.

Blue-tinted Neptune (magnitude 7.9) will spend April in the eastern pre-dawn sky, moving eastward through the stars of eastern Aquarius. The shallow morning ecliptic will keep the dim planet too close to the twilit horizon to be observable in telescopes until the latter part of the month, when it will rise in a dark sky before 5 a.m. local time.

Skywatching Terms

Gibbous: Used to describe a planet or moon that is more than 50 percent illuminated.

Asterism: A noteworthy or striking pattern of stars within a larger constellation.

Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It's easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky, while a finger covers about one degree.

Visual Magnitude: This is the astronomer's scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.

Terminator: The boundary on the moon between sunlight and shadow.

Zenith: The point in the sky directly overhead.

Night Sky Observing Tips

  • Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.
  • Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you're stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you're in the suburbs, simply turning off outdoor lights can help.
  • Prepare for skywatching: If you plan to be out for more than a few minutes, and it's not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.
  • Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you'll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it's unsafe to look at the sun without protective eyewear. See our video on how to safely observe the sun, or our safe sunwatching infographic.

Further Reading

Moon Phases: How the lunar cycle works, from full moon to new moon. Also find out when is the next full moon.

Constellations: The history of the Zodiac constellations and their place in night sky observing.

Lunar Eclipses: How they work, plus find out when's the next lunar eclipse.

Solar Eclipses: How they work, the types, and when the next one occurs.

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