The spring sky is often somewhat disparagingly referred to as one in “transition.” While it’s true that, in April, the magnificent winter constellations still draw our attention westward in the early evening sky, they nonetheless set quickly. In the second part of the night, the beautiful summer constellations are well-settled in the east, a sure sign that the warm weather is on its way. But the springtime sky is also packed with interesting constellations, and overlooking them would be our loss!
Two major constellations depicting animals dominate the starry spring sky. The first is none other than Ursa Major, the Great Bear, undoubtedly the best-known of all the constellations. At this time of the year, it is almost directly overhead in the evening. It is most famous for containing the Big Dipper, which is easily recognizable by the four stars that outline its bowl and three others that make up its long curved handle: But this asterism simply represents the Bear’s hindquarters and disproportionately long tail. The rest of the Big Bear’s body is formed by stars that are dimmer and more difficult to make out in the city.
The trick of using the Big Dipper to find Polaris, the North Star, is well known: Simply draw an imaginary line from the two outer stars in the bowl (opposite the handle), extend it outward by a factor of four or five and you’ll arrive at Polaris, the brightest star in Ursa Minor, the Little Bear. Although famous for marking the way due north, the North Star is not particularly bright and only ranks 48th brightest by apparent magnitude.
Note how the handle of the celestial ladle is bent: Just extend this natural curve and you’ll come to Arcturus, the third brightest star, which is easily recognizable by its golden colour. Arcturus is also the alpha star in the constellation Boötes, whose shape resembles that of a large kite in the sky.
Now follow the same arc of the handle past Arcturus and you’ll find Spica, Virgo’s Ear of Grain, a brilliant blue-white beauty of a star. With the exception of Spica, the stars that make up the vast constellation Virgo are relatively dim, but this region contains a large number of galaxies within reach of amateur telescopes.
The second animal constellation in the spring skies can be found below Ursa Major, due south. Draw a line between the two outer stars in the bowl (on the same side as the handle this time) and extend it downward: You’ll come to Regulus, the alpha star of Leo the Lion, one of the few constellations that actually resembles its namesake. Regulus marks the bottom of the backwards question mark pattern that outlines the Lion’s head and mane—an asterism also known as the Sickle. To the left of the Sickle is a triangle of stars that form Leo’s backside and tail.
Binoculars or a telescope will help you unlock the hidden treasures and numerous galaxies in the region of sky between Ursa Major, Leo, and Virgo.
Mars in the evening sky
As for the planets, Mars still catches our eye in the April evening sky. You’ll be able to observe it due west at nightfall. Start by looking for a brilliant orange star, to the right of the constellation Orion and at the same height in the sky: That’s Aldebaran in Taurus. Slightly to its right, you’ll also see the Pleiades star cluster, a small group of tightly packed stars that are a lovely sight in binoculars and definitely worth checking out.
Turn your gaze about 15 degrees above Aldebaran and you’ll find Mars, which also looks like an orange star, only dimmer. On April 16, the crescent Moon will slip between the Red Planet and Aldebaran; the next evening, the Moon will stand above Mars.
Jupiter and Saturn in the early morning sky
The end of the night will be all about Jupiter and Saturn. The two planets can be found a dozen degrees above the southeastern horizon at the crack of dawn. The lunar crescent will lie just below Saturn on the morning of April 6, with Jupiter shining brightly to the left of this duo. The next morning, the thin crescent Moon will hang below Jupiter.
On April 26, the full Moon will arrive less than 12 hours before its perigee—the point at which the Moon is closest to Earth. This is what is often called—somewhat exaggeratedly—a “supermoon”: In principle, this perigee full moon should appear slightly bigger than average, but in practical terms, it will be impossible to tell the difference with the naked eye because there’s no absolute reference against which to compare, and our memories often play tricks on us. However, if we compare photographs of the full Moon taken with the same camera at various times of the year, the difference will become apparent. The tides will also be higher than usual during this period.
Venus and Mercury
Let’s conclude with a challenge: Try spotting Venus and Mercury in the early evening on April 24 and 25. The two planets will be visible 20 minutes after sunset, very low above the west-northwestern horizon and just over one degree apart. On the 24th, Venus, the brighter of the pair, will shine to the immediate left of and slightly higher than Mercury. The next day, Venus will drop lower in the sky than Mercury. However, keep in mind that the two planets will be very difficult to see as they only appear 2 degrees above the horizon and set quickly around 8:30 p.m. You’ll need binoculars and a perfectly clear view of the horizon to successfully observe them.