Welcome to the Night Sky Map for April 2020! This month, we focus on lesser-known constellations that aren’t quite big or bright enough to make it into the “Big Leagues,” but are certainly still worth gazing at!
Just click here or on the image below to open the printable map—then bring outside!
Appreciating the “Minor League” Constellations
With the start of baseball season upon us, this seems an appropriate time to look at constellations that haven’t made the Big Leagues. These are the night sky’s lesser lights, constellations that are either too small or too faint to make the celestial all-star team. To maximize your ability to see the Minor Leaguers, choose a moonless night during April (see Moon phase dates here) and a viewing location as far as possible from city lights.
Look First for Leo, the Lion
First, let’s get our bearings. When you look to the south on April evenings, mighty Leo, the Lion, dominates the scene. The most distinctive part of Leo is the Sickle asterism, a pattern of six stars anchored by Regulus, the 21st brightest star in the night sky. Once you’ve spotted the Sickle, you should have little trouble tracing out the rest of Leo, culmination with bright Denebola, whose name comes from an Arabic phrase meaning “tail of the lion.”
The Smaller Lion and Berenice’s Hair
With Leo clearly in view, we can now make our way to the first few Minor Leaguers. Just above Leo lies the Smaller Lion, Leo Minor. You’ll have to make good use of your imagination, because only three of Leo Minor’s stars are easily visible, arranged in a much-flattened triangle. Moving to the east (leftward), we find Coma Berenices, Berenice’s Hair, named for Queen Berenice of ancient Egypt. It seems Berenice pledged to cut her long, flowing hair if her husband, King Ptolemy III, returned safely from battle. When he did, Berenice lopped off her golden locks, and astronomers of the time declared that they would be forever preserved in the night sky.
Like Leo Minor, Coma Berenices consists of just three main stars. However, the constellation is also home to the Coma Berenices Star Cluster, which is highlighted on our map. With your eyes alone, you will see only about five stars in the cluster, but even small binoculars will reveal several more.
The Crow and the Cup
Continuing downward, past the large constellation Virgo, we come to the compact figures of Corvus, the Crow, and Crater, the Cup. Corvus is an ancient constellation, dating back to at least 1,100 B.C., when it was known to the Babylonians as The Raven. Its four main stars form an asterism that is easy to spot, even though it bears scant resemblance to a crow. Crater is much fainter but equally old, and it does actually resemble its namesake.
To the upper right of Crater and directly blow Regulus is Sextans, the Sextant, one of the least impressive constellations of all. It’s another three-star constellation, but unlike very ancient Corvus and Crater, Sextans is a modern invention. It was first designated as a constellation in 1687 by noted Polish astronomer Johannes Hevelius.
The Water Snake
Slithering beneath the small constellations Corvus, Crater, and Sextans is Hydra, the Water Snake. Hydra is the largest of all constellations, an impressive meandering figure that spans nearly one-quarter of the sky, from its head high in the south to its tail near the eastern horizon. This constellation has been recognized since very ancient times, despite being home to only one bright star, Alphard, known as “The Solitary One.”
The Unicorn and the Crab
Hydra seems to be meandering westward toward Monoceros, the Unicorn, a faint W-shape grouping that will require you to have dark skies if you are to see it at all. The final Minor Leaguer in this part of the sky is Cancer, the Crab, which sits just above the head of Hydra and directly to the right of the Sickle, where we began our journey.
Hopefully, this tour will help you appreciate the so-called “little things.” Enjoy the April night sky!
Click here or on map below to enlarge (PDF).
Sky map produced using Chris Marriott’s Skymap Pro
Note: How to Read the Sky Map
Our monthly sky map does not show the entire sky which would be almost impossible. Instead, the map focuses on a particular region of the sky each month where something interesting is happening. The legend on the map always tells you which direction you should facing, based on midnight viewing. For example, if the map legend says “Looking Southeast,” you should face southeast when using the map.
The map is accurate for any location at a so-called “mid northern” latitude. That includes anywhere in the 48 U.S. states, southern Canada, central and southern Europe, central Asia, and Japan. If you are located substantially north of these areas, objects on our map will appear lower in your sky, and some objects near the horizon will not be visible at all. If you are substantially south of these areas, everything on our map will appear higher in your sky.
The items labeled in green on the sky map are known as asterisms. These are distinctive star patterns that lie within constellations. When getting your bearings under the stars, it’s often easiest to spot an asterism and use it as a guide to finding the parent constellation.
The numbers along the white “Your Horizon” curve at the bottom of the map are compass points, shown on degrees. As you turn your head from side to side, you will be looking in the compass direction indicated by those numbers. The horizon line is curved in order to preserve the geometry of objects in the sky. If we made the horizon line straight, the geometry of objects in the sky would be distorted.