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IN THE northern hemisphere, summer nights are marked by an asterism (a pattern of stars that isn’t an official constellation) called the summer triangle. Despite the name, the three stars that make it up aren’t just visible in this season: many stargazers in the southern hemisphere also get a glimpse of them in their winter months too.

The summer triangle is a vivid asterism, made up of the brightest stars from the constellations Aquila, Lyra and Cygnus. Altair, a star from Aquila, is the twelfth brightest in the night sky. Lyra’s Vega is only 25 light years away from us, making it the fifth brightest from our perspective. Deneb, the brightest star in Cygnus, is a blue-white supergiant and makes up part of another asterism called the northern cross.

In the northern hemisphere, look east when it is dark to find the summer triangle. Vega will shine highest in the sky, with Deneb to its left and Altair below. The triangle should be visible all night.

However, in the southern hemisphere, the asterism won’t be visible for that entire period. It will appear in northern sky a few hours before sunrise. Altair will be highest, with Vega and Deneb below. Close to the equator, Altair will be near Vega at the top.

The summer triangle is one of the easiest asterisms to find because of its brilliant stars – and because it covers a large part of the sky, it can help astronomers find their way around the sky in June, July and August. It is also beautiful to look at on its own. This year, the summer triangle will be complemented by two planetary visitors lurking nearby.

In June, after not being visible in the night sky for a few months, the gas giants will appear near the summer triangle. Saturn and Jupiter will create an almost rectangular shape, with the other two corners made up of Vega and Deneb, for the whole month.

In the northern hemisphere, the planets will appear low in the eastern sky, staying close to the horizon and rising a few hours after sunset. In the southern hemisphere, the planets will appear above the asterism. If you are unsure when or where they will turn up in your area, use a stargazing app or software like Stellarium to check ahead of time.

You won’t need dark skies to see this combination of stars and planets: all will shine brightly even in cities. If you are in a dark-sky area, you might catch the central bulge of the Milky Way making a trail across the sky through the middle of the summer triangle. Deneb is right in the middle of the disc of the Milky Way in the sky.

If you have binoculars or a telescope, look at Jupiter to get a view of its Galilean moons. All four will be visible, with Io on one side and Europa, Ganymede and Callisto forming a line on Jupiter’s other side. With a small telescope, you might see the rings of Saturn, as well as Titan, one of its moons.

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