Continuing with the fascinating world of constellations , today we're going to analyze the history and characteristics of one of the most famous in the Northern Hemisphere: Cassiopeia. This constellation consists of five stars that are brighter than the rest and have a distinctive double-W shape. It has something special about it compared to other constellations in the sky: its shape varies considerably depending on the time of year and the latitude from which it is observed.
In this article, you'll discover the deepest secrets of one of the most famous constellations in the world. Want to know the origin and history of Cassiopeia? Read on to find out all about it.
Key features
The International Astronomical Union has established approximately 88 modern constellations and another 48 Ptolemaic constellations. Of these, Cassiopeia is one of the best known and most important, both for its prominence in the sky and for the origin and mythology surrounding it.
It consists of five stars that shine brighter than the rest and is located quite close to the celestial north. In most countries in the Northern Hemisphere, Cassiopeia is visible throughout the night. Its appearance can indicate sidereal time in some areas, as well as the circumpolar constellations that are also visible.
It has a W shape that changes depending on the viewing location and the time of year. However, it always maintains that W shape.
Among its main stars we find:
- α - Schedar, 2.2, yellow. The name of this star means bosom.
- β - Caph, 2.3, white. Its name comes from the Arabic name and is 46 light years away.
- γ - Cih, about 2.5, blue-white. This star is the one that arouses the most curiosity among fans of the constellations. And it is that its name is completely unknown and has a magnitude that ranges between 3.0 and 1.6. Some scientists think that the speed it has in its rotation makes it quite unstable and that is the reason why the illusion of gas rings can be observed.
Location of Cassiopeia in the night sky
Let's learn how to find this constellation in the night sky. Being a circumpolar constellation (meaning it will always be above the horizon in the Northern Hemisphere), we can see its unmistakable W shape. It's easy to locate, as it's opposite the Big Dipper in relation to Polaris (the North Star) . The Big Dipper is much easier to identify on its own, so when you see it, simply look in the opposite direction to find the W shape that marks the location of Cassiopeia.
The center of this constellation has a declination of approximately 60°N and a right ascension of one hour. When Cassiopeia is sighted, the North Star (Polaris) can also be located , as it lies near the point where the bisectors of their angles intersect, forming the letter W. This method of finding Cassiopeia with the North Star is fundamental for navigation, as it indicates true north with considerable accuracy. Furthermore, its altitude above the horizon usually coincides with the observer's latitude.
Origin and Mythology
The origin of this constellation dates back to the legend of Queen Cassiopeia and her unfortunate life. She was the wife of King Cepheus of Joppa and had a daughter named Andromeda. Both were beautiful women, so much so that Queen Cassiopeia committed the sin of claiming that she and her daughter were more beautiful than the sea nymphs known as the Nereids. The Nereids were the daughters of a sage who lived in the sea named Nereus.
When the Nereids heard from Cassiopeia that they were more beautiful than her, they were offended and went to Poseidon to seek revenge. Poseidon did not take kindly to such claims and used his trident to flood all the coastal lands of Palestine. He also summoned the monster Cetus to attack from the depths.
On one hand, Cepheus consulted the oracle of Ammon to learn how he could save his people. The only way was by sacrificing his daughter Andromeda to Cetus. Therefore, Andromeda was chained to the rocks on the coast of Joppa. When Cetus saw her chained and went to attack her, Perseus appeared to fight him in exchange for Andromeda's hand in marriage.
Later, when Perseus and Andromeda were married, Phineus, a jealous former suitor of Cassiopeia, appeared. He sent an army of 200 warriors against Perseus , who then produced Medusa's severed head to petrify them all.
Finally, as punishment for everything that had happened, Poseidon placed Cassiopeia in an indecent and unattractive position in the sky. Furthermore, her story is linked to other constellations, such as Andromeda , which makes it even more interesting within the realm of mythology.
The ghost of Cassiopeia
The so-called Ghost of Cassiopeia is nothing more than a nebula located 550 light-years away . It has an ethereal glow and is often mistaken for typical paranormal ghost sightings here on Earth. It is formed by the energy of molten stars that release fluid gases and dust, creating this curious appearance.
Its brightness and shape resemble a cloud similar to those found in paranormal phenomena. However, this cloud of gas and dust is composed of hydrogen continuously bombarded by ultraviolet radiation from a nearby blue giant star called Gamma Cassiopeiae. This radiation causes the star to shine with red light, and the blue portion is light reflected from the dust in the nebula.
This is the explanation of the famous ghost of Cassiopeia. However, to see it you need a very powerful telescope that not everyone has access to.
