What is a constellation?
Constellations are patterns in the night sky often made up of the most prominent stars with the naked eye. Technically, a constellation defines not only the group of stars that form its patterns, but also the region of the sky in which it rests.
There are 88 constellations across the sky between the northern and southern hemispheres, and on both parts of the celestial sphere, these star patterns differ.
The current list, which includes constellations such as Orion, Cassiopeia, Taurus, and the Plow, has been recognized by the International Astronomical Union (IAU) since around 1922 and is based on the 48 that were previously identified by the Greek astronomer Claudius Ptolemy.
Constellations are often named after and take the form of gods, hunters, princesses, items, and mythical beasts associated with Greek mythology.
However, sometimes a great imagination is required to bring to light what some constellations are supposed to represent!
Some of the more obvious stars in a constellation are often given names, and in general the most conspicuous stars in each constellation are assigned Greek letters with the brightest taking the first letter of the Greek alphabet (alpha), the second brighter by taking beta and so on. For example, the brightest star in Lyra is Vega, which is also called alpha Lyrae.
A constellation is a group of visible stars that form a pattern when viewed from Earth.
The pattern they form can take the shape of an animal, a mythological creature, a man, a woman, or an inanimate object such as a microscope, compass, or crown.
Constellation Definition
The Merriam-Webster Dictionary defines a constellation as «a group of stars that form a particular shape in the sky and have been given a name» or «any of 88 arbitrary configurations of stars or an area of the celestial sphere that covers any of these configurations.»
Britannica defines the term, as used in astronomy, as «any of certain groupings of stars that were imagined – at least by those who named them – to form conspicuous configurations of objects or creatures in the sky.»
How many constellations are there?
The sky was divided into 88 different constellations in 1922. This included 48 ancient constellations listed by the Greek astronomer Ptolemy, as well as 40 new constellations.
Where do the constellations come from?
OK, so we know that constellations are useful for remembering the stars, but why would people want to do that (besides astronomers, that is)? After all, I said at the beginning that the farmers invented the constellations. Because they did that?
Was it for some religious purpose?
Yes and no. All over the world, farmers know that for most crops, you plant in the spring and harvest in the fall.
But in some regions, there is not much difference between the seasons. Since different constellations are visible at different times of the year, you can use them to tell what month it is.
For example, Scorpius is only visible in the sky of the northern hemisphere during the summer. Some historians suspect that many of the myths associated with the constellations were invented to help farmers remember them. When they saw certain constellations, they knew it was time to start planting or harvesting.
This dependence on the sky became a strong part of many cultures. Perhaps there is something about the mystery of the night sky that makes people want to tell stories about the constellations.
The image on the left is an ornate star map printed in 1835. Like the others, it shows the great hunter Orion. In this case, he is holding a lion’s head instead of his traditional bow or shield.
He has an anxious look as he stalks Taurus, the Bull. Behind him, his faithful dog, Canis Major, chases Lepus the Hare.
The constellations have changed over time. In our modern world, many of the constellations have been redefined so that now every star in the sky is in exactly one constellation.
In 1929, the International Astronomical Union (IAU) adopted the official constellation boundaries that defined the 88 official constellations that exist today.
star maps
The 88 different constellations divide the entire night sky as seen from all points on Earth. Star charts are made up of the brightest stars and the patterns they make that give rise to the names of the constellations.
Star maps represent the position of the stars as we see them from Earth.
The stars in each constellation may not be close to each other at all. Some of them are bright because they are close to Earth while others are bright because they are very big stars.
Hemispheres and seasons
Not all constellations are visible from any point on Earth. Star maps are typically divided into maps for the northern hemisphere and maps for the southern hemisphere.
The season of the year can also affect which constellations are visible from where they are located on Earth.
famous constellations
Here are some of the most famous constellations:
Orion
Orion is one of the most visible constellations. Due to its location, it can be seen all over the world. Orion is named after a hunter from Greek mythology. Its brightest stars are Betelgeuse and Rigel.
Great Bear
The Big Dipper is visible in the northern hemisphere. Means «Big Bear» in Latin. The Big Dipper is part of the Ursa Major constellation. The Big Dipper unit is often used as a way to find a northerly direction.
Little Bear
Ursa Minor means «Little Bear» in Latin. It lies close to the Big Dipper and is also patterned with a small ladle called the Little Dipper as part of its larger pattern.
Draco
The Draco constellation can be seen in the northern hemisphere. It means «dragon» in Latin and was one of the 48 ancient constellations.
Pegasus
The constellation Pegasus is named after the flying horse of the same name from Greek mythology. It can be seen in the northern sky.
Draco constellation
the zodiac
The constellations of the zodiac are the constellations that are located within a band that is about 20 degrees wide in the sky. This band is considered special because it is the band where the Sun, the Moon and the planets move.
There are 13 zodiacal constellations. Twelve of them are also used as signs for the zodiacal calendar and astrology.
CapricornAquariusPiscesAriesTaurusGeminiCancerLeoVirgoLibraScorpiusSagittariusOphiuchus
Uses of Constellations
Constellations are useful because they can help people recognize the stars in the sky. By looking for patterns, stars and places can be much easier to spot.
The constellations had uses in ancient times. They were used to help keep track of the calendar. This was very important so that people knew when to plant and harvest crops.
Another important use for the constellations was navigation. When finding the Little Dipper it is quite easy to see the North Star (Polaris). Using the height of the North Star in the sky, navigators could calculate their latitude helping ships cross the oceans.
Number of Constellations
In order to create some kind of structure in the heavens, in the early 1920s the International Astronomical Union decided to create 88 constellations that would be officially recognized by all astronomers.
The breakdown consists of 17 human or mythological characters, 29 inanimate objects, and 42 animals.
He was given an official name, as well as a three-letter abbreviation that corresponds to the real name. So, for example, there is AQR for Aquarius, the sign of the zodiac, or CHA for Chameleon, the animal.
Interesting Facts About Constellations
The largest constellation by area is Hydra, which represents 3.16% of the sky.
The smallest is the Crux, which only occupies 0.17 percent of the sky.
The small patterns of stars within a constellation are called asterisms. These include the Big Dipper and the Little Dipper.
The word «constellation» comes from a Latin term meaning «set of stars.»
Twenty-two different constellation names start with the letter «C».
The International Astronomical Union, formed in 1919, set out to define the official boundaries between the constellations in the 1920s.
Eugène Delporte adjusted the modern limits along the lines of right ascension and declination for the epoch B1875.0. As a result of the precession of the equinoxes, the boundaries will have to be readjusted eventually.
Of the 88 official constellations, 36 are in the northern sky and the remaining 52 in the south.
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