THE 20th of March marks the vernal, or spring, equinox in the northern hemisphere, and the autumn equinox in the southern hemisphere. On this day, most places in the world will get around 12 hours of daylight. The days are getting shorter in the southern hemisphere, while many of us in the northern hemisphere are looking forward to signs of spring.
But wherever you are, this is a great time to spot a pattern of stars known as the Spring Triangle. It is worth looking for no matter where you live, even in areas with light pollution, because the three stars that make it up are bright enough to compete with city lights.
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Its name may suggest it is only visible to those of us entering spring, but the Spring Triangle (pictured, above, as viewed from Canada) can be seen as far south as Queenstown, New Zealand. The asterism 鈥� a pattern of stars that isn鈥檛 an official constellation 鈥� is made up of three stars from three constellations: Arcturus in Bo枚tes, Spica in Virgo and Denebola in Leo.
It is easiest to start with Arcturus. In the southern hemisphere, Arcturus will be the bright star near the horizon directly due north-east about 5 hours after sunset. It will then be visible throughout the night, moving north as the night goes on. Arcturus is the fourth brightest star in the sky, so it should stand out from the others around it.
In the northern hemisphere, you can use the Plough, or Big Dipper, which is part of the constellation Ursa Major. Look at the line of stars that forms its handle, then follow the arc of this curve away from the Plough and you will get to a bright star, Arcturus. It will be visible near the eastern horizon from as soon as the sun has set. I like to remember this technique by thinking of 鈥渁rc to Arcturus鈥�.
Once you have found Arcturus, the rest of the triangle can go from here. In the southern hemisphere, Spica in Virgo will be the bright star almost directly above Arcturus, while Denebola, in Leo, will make the third point in an almost equilateral triangle, off towards the north, or left, of them both. In the northern hemisphere, the triangle will appear in a different formation. Spica will be the last star to rise, so you might have to wait until 3 hours after sunset to see it low in the eastern sky. It will appear below and to the right of Arcturus. Above and to the right of Spica will be Denebola.
Wherever you are looking from, you can make sure you have the correct stars using any free stargazing app. Or you can check that Denebola is the right star by looking away from the triangle in the direction of Denebola 鈥� if you see what appears to be an upside-down question mark (in the southern hemisphere) or a backwards question mark (in the northern hemisphere), you have found the sickle of Leo, and you are in the right place.
Abigail Beall is a features editor at 麻豆传媒 and author of The Art of Urban Astronomy. Follow her @abbybeall
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