CONSTELLATIONS

What is a constellation?

       “Twinkle, twinkle, little star,

         How I wonder what you are!”

    I hope we all have read this poem in our childhood. From childhood, we all have a fascination with stars, planets, and all about our universe! When I looked at the sky as a child, I made some designs by connecting the stars in my mind. After reading some books, I got to know there are actually some grouping of stars and they also have names. The word constellation comes from the late Latin term “cōnstellātiō” (Set of stars).

  So, according to the oxford dictionary constellation is, a group of stars forming a recognizable pattern that is traditionally named after its apparent form or identified with a mythological figure.

Figure 1 The constellations

  

  History of constellations

  All cultures have long traditions of using astronomy as a tool of survival. They developed astronomical methods for navigation in space and time, in particular, to determine their calendars: to measure equinoxes and solstices, and to predict the seasonal behavior of nature. For the Inuit in the far north, this was the prediction of the return of the Sun; for the Egyptians, it was the flood of the Nile; for the Babylonians and others in the monsoon zone, it was the predominant direction of the wind; and for the Aboriginal Australians, it was the emu’s breeding cycle. 

Lascaux Cave is a network of caves near the village of Montiganc. Some of the cave paintings could be the representation of constellations. It has been said that there are 17,000 years old cave paintings of Taurus, Orion’s belt.

                                

  Now let’s talk about “MUL.APIN”. It is the title of a Babylonian collection. It has been suggested that it deals with many astronomy perspectives. It is the earlier star catalogs. The texts provide us the names of almost 66 stars.

  Chinese and Inca both grouped their constellations according to their seasons. Their constellations formed with dark clouds of the Milky Way gala

  The Ancient Greek word for constellation is ἄστρον (Astron). These terms historically referred to any recognizable pattern of stars. The constellations, as described in Greek mythology, were mostly god-favored heroes and beasts who received a place amongst the stars as a memorial of their deeds, like, Gemini, Draco, Cygnus etc.  

   88 Modern constellations

  In modern astronomy, there are 88 constellations recognized by IAU in 1922.  These constellations are based on mostly Ptolemy’s Almagest (Mathematical and astronomical thesis about the motions of stars and planets) and Aratu’s works. 48 of the constellations are known as ancient (which means they were talked about by Greeks, Babylonians, Chinese, and more earlier peoples). The rest of the constellations are discovered in the modern astronomy era.

Figure 3 IAU designated constellations in equirectangular projection

   3 Interesting constellations    

  Though there are a lot of constellations, I am going to discuss about 5 constellations.

  1. Hydra

 Name origin: Hydra means “Water snake”. It represents the fresh-water serpent that Hercules was forced to defeat as one of his twelve labors.

Figure 4Hydra and surrounding constellations

 Mythology:  It is the adaptation of Babylonian constellations.

   The water-snake features in two legends. First, and most familiar, the Hydra was the creature that Hercules fought and killed as the second of his famous labors. The Hydra was a multi-headed creature, the offspring of the monster Typhon and the half-woman, half-serpent called Echidna. Hydra was thus the sister of the dragon that guarded the golden apples, commemorated in the constellation Draco. Hydra reputedly had nine heads, the middle one of which was immortal.

   Stars in Hydra:  Hydra contains approximately 238 stars. Among them, Alphard is the brightest one. It contains three messier objects: Messier 48, Messier 68, and Messier 83 and also there are other deep sky objects.

 

Figure 5 Hydra constellation in the night sky

  2. Ursa Major

   Name origin:    Ursa Major means “Great Bear”, in Latin. It is a constellation of the Northern Hemisphere. Many people around the world, thought that its design looks a lot like a Bear with a long tail.

   Mythology:   In Hinduism, Ursa Major is known as Saptarshi. Here each of the stars represents one of the seven sages.

  This constellation is also found in the King James version of the bible (An early modern translation of the Christian Bible).

   Ancient Finns believed that the bear was lowered to earth in a golden basket off the Ursa Major, and when a bear was killed, its head was positioned on a tree to allow the bear's spirit to return to Ursa Major.

   In Greek mythology, Zeus fell in love with Callisto. Hera changed her into a bear out of jealousy. Her son Arcus (the namesake of Arcturus, the alternate name for the constellation Boötes) came upon her in the forest and she ran to greet him. Not knowing the bear was his mother, he was about to kill her. To save her, Zeus turned Arcus into a smaller bear, grabbed them both by their tails, and flung them into the sky, causing their tails to be stretched.

   Stars of Ursa Major: The dimmest of the seven stars in Ursa Major, is Megrez. Others are, Alkaid, Mizar, Alioth, Phecda, Merak, Dubhe.

Figure 6 The Ursa Major and its stars

   3. Hercules

    Name origin: This constellation is named after the Roman mythological hero adapted from the Greek hero Heracles.

    Mythology: It is located in the Northern sky. Its origin was unclear near the Greeks. Heracles was the son of Zeus and Alcmene. When he was an infant, Zeus laid him near Hera, while she slept.  Later Heracles went to serve Eurystheus, king of Mycenae. King Eurystheus gave Heracles a series of tasks, known as the Labours of Heracles. The first was to defeat the Nemean lion, a beast with impenetrable skin. Heracles was successful to kill the Lion. The Nemean lion is represented by the constellation Leo. The second task was to destroy the Hydra, represented by the Hydra constellation, a monster with multiple heads. As he fought with the beast, Hera sent a crab to distract him. Heracles did away with the crab, and Hera placed it in the sky as the constellation Cancer. Heracles completed all 12 tasks of Eurystheus. Later, Heracles married  Deianeira, the daughter of King Oeneus. Much later, she became worried that Heracles’ attention was wandering to another woman and she gave him a poisoned shirt. The poison in this shirt started burning the part of Heracles, which was mortal. the immortal part joined Zeus and the other gods. Zeus placed Heracles in the sky as the constellation now known by its Roman name, Hercules.

Figure 7 Hercules constellation in the night sky

Stars in Hercules:  There are many variable stars (whose brightness as seen from Earth changes with time). Rasalgethi (alpha Herculis) is one of them. There are also double stars (pair of stars that appear close to each other as viewed from Earth) like, Marsic, Zeta Hercules, Rho Hercules, etc.

Article by-

Nandalal Debanath (Student)