Aquila Constellation: Brightest Star, Finding Its Shape, and Star Charts

What Is the Aquila Constellation?

Aquila, Latin for "eagle," is one of the 88 modern constellations and was also included among the 48 constellations listed by the 2nd-century astronomer Ptolemy. It lies near the celestial equator, making it visible from most of the world at some point in the year. In Chinese astronomy, the stars of Aquila were part of the region associated with the celestial river and the weaving maiden, a reminder that cultures across the globe have woven stories around this patch of sky.

The constellation's most recognizable feature is its bright alpha star, Altair, which anchors a loose grouping of stars that many observers see as an eagle with outstretched wings. Aquila is not among the largest constellations, but its position along the Milky Way gives it a rich backdrop of faint stars and deep-sky objects.

Altair: The Brightest Star of Aquila

Altair (Alpha Aquilae) is the brightest star in Aquila, with an apparent magnitude of about 0.77. It is a white main-sequence star located roughly 16.7 light-years from Earth, making it one of the nearest bright stars to our solar system. Altair is notable for its rapid rotation, which flattens the star at its poles and causes its equatorial diameter to be significantly larger than its polar diameter.

Altair forms one corner of the famous Summer Triangle, an asterism that also includes Vega in Lyra and Deneb in Cygnus. This triangle is a helpful guide for finding Aquila, as Altair is the southernmost and second-brightest of the three stars. The star's name comes from the Arabic "al-nasr al-ta'ir," meaning "the flying eagle," a testament to the constellation's ancient identity.

How to Find Aquila in the Night Sky

Locating Aquila is straightforward once you know the Summer Triangle. Here are steps to find it:

• Start with the Summer Triangle: On a clear summer or autumn evening, look high overhead for the bright stars Vega, Deneb, and Altair. Vega is the brightest and highest in the northern sky; Altair is the one farthest south.
• Use Altair as your anchor: Once you spot Altair, you have found the head of the eagle. The star is flanked by two fainter stars, Tarazed (Gamma Aquilae) and Alshain (Beta Aquilae), which form the eagle's neck or shoulders.
• Trace the wings: From Altair, extend imaginary lines outward to stars like Zeta Aquilae and Theta Aquilae to sketch the wings. The pattern is not as compact as some constellations, but the eagle shape becomes apparent with a little imagination.