Location, Names, Distance, and Magnitude

Altair is the 12th brightest star in the night sky and is part of the Aquila constellation. Aquila is the 22nd largest star constellation in the sky, occupying an area of 652 square degrees in the fourth quadrant of the northern hemisphere. Aquila is visible between the latitudes +90° and -75°. Altair is also part of The Summer Triangle made with the help of Vega and Deneb. These three stars form a triangle and are the brightest stars in their separate constellations. Aquila is Latin for eagle and is visible from the northern hemisphere in the summer months because of the path the Earth takes around the Sun. Altair is visible from Calgary during these months. We can’t quite see Altair in the winter months because the star is located in the direction of the sun during the day and is consequently blocked out by the suns brightness. In the month of July, Altair is visible directly east at 10 p.m in mid-northern latitudes. Another name for Altair is Alpha Aquilae.

Altair is approximately 16.6 light years away or 5.1 parsecs. Because Altair is relatively close, the distance to it can be calculated using stellar parallax. Measuring the angle Altair moves in the sky as we move in orbit around the sun, combined with the known distance we travel, we can use this to calculate the distance away using basic trigonometry. With an apparent magnitude of 0.76 and absolute magnitude of 2.2, Altair is the 12th brightest star in the entire sky. The sun’s absolute magnitude is -26.7 which means that at the distance Altair is to us, if the sun took its place, we wouldn’t be able to see it. Apparent magnitude is the brightness of a celestial object as observed from earth, while the absolute magnitude is how bright that object would appear at a distance of 10 parsecs. These measurements mean that if Altair were substituted for our sun, at the distance the sun is now, life on Earth wouldn’t survive because Altair shines with 11 times the sun’s visible light.

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