Summer Triangle

A bright Moon is a beautiful sight – unless you have your heart set on seeing the stars. In that case, it’s a pest. The Moon’s glare overpowers many of the stars in the sky.

But some manage to shine through even the brightest moonlight. Tonight, for example, even though the Moon is about 95 percent full, three stars are quite easy to find: Vega, Deneb, and Altair – the Summer Triangle. The triangle stands high in the eastern sky at nightfall, and climbs directly overhead later on.

Its brightest member is Vega, at the top of the triangle. It’s about 25 light-years away. That means the light you see from the star tonight began its trek across the galaxy in the year 2000. Vega is bigger and heavier than the Sun, and almost 50 times brighter.

Deneb is to the lower left of Vega. Its distance is uncertain; more about that tomorrow. What is certain is that it’s a supergiant – many times bigger and more massive than the Sun, and tens of thousands of times brighter. And its fate is pretty well known, too: Deneb is likely to explode as a supernova sometime in the next few million years.

Altair is farther to the lower right of Vega. It’s the closest member of the triangle – just 17 light-years away. It’s a lot like Vega, just not quite as impressive. Still, it’s easy to spot through the moonlight – a member of the bright Summer Triangle.

Script by Damond Benningfield