Look up with the April 2018 sky map to navigate the stars and constellations in the night sky. On this page is both a color sky map and a black and white printable map to bring outside!
Just click here or on the image below to open the printable map—then bring outside!
Highlight for April: Planets on Parade
Most of us prefer the convenience of doing our sky gazing in the evening. We can enjoy the night sky and still get to bed at a civilized hour. Sometimes, however, you simply MUST get up early in the morning to see the best astronomical sights. So it is in April when three bright planets are on display before dawn. You’ll need to venture outside around 5:00 a.m. to catch the show.
Most of the action on this month’s sky map occurs low in the south-southeast sky. Before dawn on April 7, there is a conjunction of the Moon and the planets Mars and Saturn just above the “Teapot” asterism (unofficial star pattern) in the constellation Sagittarius the Archer. Reddish Mars and yellowish Saturn will spend most of April in this vicinity, but the Moon joins them only on the morning of April 7.
As shown on the map, the Moon begins April far to the right, directly above the bright star Spica in the constellation Virgo the Virgin. Through the first ten days of April, the Moon moves rapidly to the right, passing near the planet Jupiter on April 3 and 4, reaching Mars and Saturn on April 7, when it will be half illuminated. By the morning of April 10, the Moon will be far to the left on our map, a handsome crescent just above the horizon.
Of the three planets on the map, Jupiter appears by far the brightest. Other than the Moon, Jupiter is the brightest object on the map. What makes one planet brighter than another? There are three factors: size, distance, and reflectivity (formally known as albedo). Mars is small rocky planet that is not very reflective. Compare that to Saturn and Jupiter, which are both “gas giants,” huge globes wreathed in bright, highly reflective clouds. On the other hand, Mar is much, MUCH closer than the two larger planets. So, little Mars is currently brighter than gigantic Saturn! Jupiter is larger and closer than Saturn, and it’s just as reflective. Thus, at the current time, Jupiter is the brightest planet on the map, outshining Mars by virtue of being larger and more reflective and outshining Saturn because Saturn is much farther away.
Saturn and Jupiter are far enough from Earth that their positions barely change all month long. Mars, on the other hand, moves steadily from right to left, passing quite close to Saturn on April 2 and 3. If you rise early and view the planets several days in a row, you’ll notice Mars’ location changing every day.
April 2018 Sky Map
Click here or on image below to enlarge this map (PDF).
Sky map produced using Chris Marriott’s Skymap Pro
Another lovely sight on the April map is the beautiful constellation Corona Borealis the Northern crown. It resembles a delicate tiara at the upper center of the map.
Four bright stars grace our map. Starting in the upper right we find Arcturus, the 4th brightest star of all. Other stellar notables include Altair, Antares (note its slightly reddish color, similar to that of Mars), and Spica. These three are the 12th, 15th, and 16th brightest stars, respectively.
In the center of our map is the large constellation Ophiuchus the Serpent Bearer. In his hands, Ophiuchus holds the two parts of Serpens, the Serpent. Serpens is the only constellation that is physically divided into two parts, known by their Latin names Serpens Caput (serpent head) and Serpens Cauda (serpent tail).
Enjoy astronomy? Check out Bob Berman’s column, “This Week’s Amazing Sky.”