Aquila (constellation)

Look up at the night sky.

You can see an eagle. It is made of stars.

This eagle lives in the Milky Way. It is a very bright group of stars. You can see it best in the summer.

One star is very bright. Its name is Altair. It is part of a big shape called the Summer Triangle.

Many other things live here too. There are clouds of dust and gas. There are also many groups of stars.

People have looked at this eagle for a long time. It is a special part of our sky.

Aquila is a group of stars in the sky. Its name is Latin for "eagle."

Many people see an eagle in these stars. In old stories, this eagle carried thunderbolts for Zeus.

You can see Aquila best during the northern summer. It sits along the Milky Way. This is a big path of stars in our sky. Because it is in the Milky Way, it has many objects. You can find star clusters and nebulae there. A nebula is a cloud of dust and gas in space.

The brightest star is Altair. It is one of the closest stars we can see with our eyes. Altair is 17 light-years away. It is part of a large shape called the Summer Triangle.

This shape uses three bright stars.

Aquila also has a very large object. It holds part of the Hercules–Corona Borealis Great Wall. This is a massive group of galaxies. It is the biggest structure known in the universe. It is 10 billion light-years long!

Aquila is a beautiful constellation located on the celestial equator. Its name is the Latin word for "eagle."

Many people look at these stars and see a great bird. In Greek-Roman myths, this eagle carried the thunderbolts of Zeus. It is also part of a famous shape called the Summer Triangle. This shape uses three bright stars to guide your eyes. Altair is the brightest star in the whole group.

You can see Aquila best during the northern summer. It sits right along the Milky Way path. Because it is in this busy part of space, it holds many star clusters and nebulae. These are clouds of dust and gas. However, most galaxies in this area are quite dim.

Watching the stars in Aquila is like looking at a busy cosmic neighborhood. The brightest star, Altair, is very close to us at only 17 light-years away. It is much bigger and brighter than our Sun. Altair spins so fast that it is not a perfect circle. Instead, it is flattened at the top and bottom like a squashed ball. Other stars in the group have very different lives. For example, Tarazed is a huge orange star far away. There is also a star called Eta Aql that changes brightness. It goes from dim to bright every 7.2 days.

This happens because it is a Cepheid variable star.

People have studied these stars for a very long time. An astronomer named Ptolemy described Aquila in the second century. Before him, thinkers like Eudoxus and Aratus also wrote about it. Later, the International Astronomical Union named it one of the 88 official constellations. Romans sometimes called it Vultur volans, which means "flying vulture." In 1784, a man named Edward Pigott found the star that changes brightness. In 1918, Zygmunt Laskowski saw a very bright nova. A nova is a sudden flash of light from a star. This flash was the brightest one seen since humans used telescopes.

Aquila is home to some truly giant things in space. It contains a huge area called W51. This is a nursery where new stars are born. It is about 350 light-years across, which is a huge distance.

You can also find the Hercules–Corona Borealis Great Wall here. This is a massive wall of galaxies. It is 10 billion light-years long. This is the largest structure we know of in the entire universe. It is a wonderful example of how big space can be.

Different cultures around the world saw different things in these stars. In China, the stars tell a sad love story. The stars Altair and Vega are separated by the Milky Way river. In Hawaii, people called Altair "Humu." This name means to bind parts of a fishhook together. The Māori people called it a "Pillar of the Sky." Even in ancient Egypt, it might have been seen as the falcon of Horus. These stories show how the same stars can mean so many things to different people.

Aquila is a prominent constellation located on the celestial equator. Its name is the Latin word for "eagle."

In Greco-Roman mythology, this constellation represents the eagle that carried the thunderbolts of Zeus, or Jupiter. It is also famously known as one of the three corners of the Summer Triangle asterism. This large shape in the night sky is formed by three bright stars. Altair is the brightest star in Aquila and serves as a key vertex for this triangle. Because Aquila lies along the path of the Milky Way, it contains many rich starfields. This location means the constellation is home to many star clusters and nebulae. However, most galaxies found within its borders are quite dim.

The stars within Aquila exhibit many different physical processes and characteristics. The brightest star, Altair, is an A-type main-sequence star. It is located only 17 light-years from Earth. Altair is significantly larger and more powerful than our Sun. It has 1.8 times the Sun's mass and 11 times its luminosity. This star rotates so rapidly that it takes on an oblate shape. This means the star is flattened at its poles due to its fast spinning. Other stars, like Tarazed, are orange-hued giant stars located 460 light-years away. Some stars in this region are also variable. For instance, the star Eta Aql is a Cepheid variable star. This means its brightness changes on a regular cycle. It has a period of 7.2 days between its minimum and maximum brightness.

Aquila contains various types of deep-sky objects that scientists study to understand the universe. One notable feature is the W51 stellar nursery. This is a massive region where new stars are born. W51 is approximately 350 light-years across. It is located about 17,000 light-years from Earth. Although it is huge, thick interstellar dust makes it opaque to visible light. Astronomers must use X-ray and infrared telescopes to see it clearly. The constellation also hosts several planetary nebulae. NGC 6751, known as the Glowing Eye, is a nebula about 0.8 light-years in diameter. Other objects include the open cluster NGC 6709, which contains roughly 305 confirmed member stars.

The history of Aquila involves many famous astronomers and observers. The second-century astronomer Ptolemy included Aquila in his catalog of 48 constellations. Before him, Eudoxus and Aratus also mentioned the constellation in the fourth and third centuries BC. The Romans had different names for these stars, such as Vultur volans, or "flying vulture." In 1784, Edward Pigott discovered the variability of the star Eta Aql. A major event occurred in 1918 when Zygmunt Laskowski observed a bright nova. This event, named Nova Aquilae 1918, briefly outshone Altair. It was the brightest nova recorded since the invention of the telescope.

Some of the most massive structures in existence are associated with this region of the sky. Astronomers discovered the Hercules–Corona Borealis Great Wall in November 2013. This structure is located within the area of Aquila. It is estimated to be 10 billion light-years in size. This makes it the largest single mass concentration of galaxies known in the universe. The scale of such an object helps scientists understand the large-scale structure of space. Even our space probes will interact with this constellation's stars. The Pioneer 11 probe is expected to pass near the star Lambda Aquilae in about 4 million years.

Different cultures have interpreted the stars of Aquila in unique ways. In Chinese astronomy, the stars are part of the Heavenly Market Enclosure. The stars also tell a story of separation in the Qi Xi legend. In this tale, Altair and Vega are separated by the Milky Way. In Hinduism, the constellation is linked to the deity Garuda. Polynesian cultures also had many names for these stars. In Hawaii, Altair was called Humu, which refers to binding a fishhook. The Māori people called Altair Poutu-te-rangi, meaning "Pillar of the Sky."

Studying Aquila helps us connect many different fields of science. By observing the Cepheid variables in the constellation, astronomers can measure distances in space. These stars act as cosmic yardsticks because their brightness changes predictably. The study of the W51 nursery connects to the science of how stars form from gas and dust. Even the study of the Hercules–Corona Borealis Great Wall helps us understand cosmology. This is the study of the origin and evolution of the entire universe. Aquila is not just a group of stars, but a laboratory for understanding the cosmos.