The Evening Sky in April 2025
Jupiter is the ‘evening star’, appearing low in the northwest soon after sunset and setting around 9 pm NZST mid-month. The Moon will be to the right of Jupiter on the 3rd. Mars is low in the north at dusk, looking like a medium bright orange star. The Moon will be near Mars on the 5th and 6th.
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 the hunter 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.
At the beginning of the month Mars is just above Pollux, the brighter of the two stars making the heads of Gemini the twins. Below Pollux is Castor, the other twin. 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.
Through the month Mars moves left and upward. Around the 10th it is in line with the twins. By the end of the month it is close to the Praesepe star cluster. Praesepe looks 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. It is 600 light-years away. It is around 600 million years old so its biggest and brightest stars have long ago burnt out.
Right of Praesepe is the 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 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.
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 in the eastern pre-dawn sky. At the beginning of the month Venus rises due east an hour before the Sun. It moves quickly up the sky morning to morning. By mid-month it will be rising 2½ hours before the Sun, a brilliant object in the dark sky. Then Saturn will be to the right of Venus and Mercury will be below Saturn. The Moon will be above Venus on the morning of the 25th and beside Mercury on the 26th.
*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.
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