The Evening Sky in April

Download a PDF containing this chart, additional charts for specific areas of the sky and descriptions of interesting objects visible at this time of year.

The Evening Sky in April 2024

Jupiter is the ‘evening star’ at the beginning of the month, setting 1½ hours after the Sun (so isn’t on the chart). It slips steadily lower, disappearing in the twilight by the end of the month.

Sirius, the brightest true star, appears midway down the northwest sky at dusk. It is soon followed by Canopus, southwest of the zenith. Below Sirius are bluish Rigel and orange Betelgeuse, the brightest stars in Orion. Between them is a line of three stars: Orion's belt. To southern hemisphere star watchers, the line of three makes the bottom of 'The Pot', now tipped on its side.

Below and right of Sirius is Procyon marking the head of Canis Minor one of the two dogs following Orion across the sky. Sirius marks the head of Canis Major, the big dog. The big dog's hindquarters are made by the bright stars above Sirius.

Low in the north below Procyon are Pollux and Castor, the heads of Gemini the twins, making a vertical pair of stars. Though related in myth, the Twins are quite different from each other. Pollux is an orange star 31 times brighter than the sun and 34 light-years (l.y)* from us. Castor is a hot white star about 47 times the sun's brightness and 51 l.y. away. The Moon will be beside Pollux on the 15th.

Above and right of The Twins is the Praesepe star cluster, looking like a hazy spot to the eye. It marks the shell of Cancer the Crab. Praesepe is also called the Beehive cluster, the reason obvious when it is viewed in binoculars. Praesepe is 600 light-years away. Its age is around 600 million years so its biggest and brightest stars have long ago burnt out.

Right of Praesepe, almost due north, is a medium-bright star Regulus. It is the brightest star in Leo the Lion. The curve of stars below Regulus outlines Leo's mane, upside down in our southern hemisphere view. A crooked vertical line of stars right of Regulus makes Leo's hind quarters with the brighter star further right being his tail. The Moon will be in the curve of the Lion's mane, below Regulus, on the 18th.

The lone bright star due east is Spica, the brightest star in Virgo. Spica marks the ear of wheat that the Roman goddess Ceres is holding. From her we get the word cereals for grain crops. Above Spica is the roughly kite-shaped constellation of Corvus the Crow. Some navigators called it "Spica's spanker (spinnaker)", the sail that towed Spica across the sky. Corvus was a handy cross-check that they were sighting on the right star. The full Moon will be just below Spica on the 23rd.

Crux, the Southern Cross, is high in the southeast. Below it, and brighter, are Beta and Alpha Centauri, often called 'The Pointers'. Alpha Centauri is the closest naked-eye star, 4.3 light-years away. Beta Centauri, like most of the stars in Crux, is a blue-giant star hundreds of l.y. away. Canopus is also a very luminous distant star; 13 000 times brighter than the sun and 300 l.y. away.

The Milky Way is brightest in the southeast above Crux. It can be traced to nearly overhead where it fades and becomes very faint in the northwest, right of Orion. The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the sun is just one.

The Clouds of Magellan, LMC and SMC are midway down the southwest sky, easily seen by eye on a dark moonless night. They are two small galaxies about 160 000 and 200 000 light years away.

Bright planets are low in the eastern pre-dawn sky. Mars and Saturn, the same brightness, make a vertical pair at the beginning of the month. Mars is reddish; Saturn cream-coloured. Brilliant Venus is directly below them, rising around 5:30 NZST. Saturn moves up the sky, night-to-night, while Mars stays put. On the morning of the 11th they will be just a full-moon’s width apart. After that Saturn moves higher. At the end of the month Mercury appears, making an equally spaced line of Saturn, Mars and Mercury down the sky. By then Venus is rising at 6:30, just 50 minutes before the Sun. The thin crescent Moon will be just below Venus on the 8th.

*A light year (l.y.) is the distance that light travels in one year: nearly 10 million million km. Sunlight takes eight minutes to get here; moonlight about one second. Sunlight reaches Neptune, the outermost major planet, in four hours. It takes four years to reach the nearest star, Alpha Centauri.

Notes by Alan Gilmore,
University of Canterbury's Mt John Observatory, 
P.O. Box 56, 
Lake Tekapo 7945,
New Zealand.