The constellation of the Little Bear
Yes... Unfortunately, in the more and more enlightened cities it becomes difficult to find this small constellation, of fundamental importance when neither compasses nor GPS satellites and related satellite navigators still existed: the navigators (the real ones) knew that the polar star indicated (even if not precisely) the direction of the North: we know that due to the precession of the equinoxes the North Celestial Pole (PNC) moves (very irregularly!) every year, just a little, but a lot that in thousands of years is felt. Thanks to Stellarium I have photographed the PNC for several years, past and future, to understand how much was and will be valid to say that the North Star indicates the North. Here are the photos I took with the year and the approximate distance between the PNC and the Polar:
|2000 B.C.||second millennium B.C.||22nd and passing|
|753 B.C.||founding of Rome||over 15°|
|64||fire of Rome by Nero||just over 11|
|1000||the first millennium||just over 6°|
|1492||the discovery of America||just over 3°|
|1770||James Cook lands in Australia||nearly 2nd|
|2011||today||just over 40′|
|2102||minimum distance Polar-PNC||27’37”|
|4000||distant future||more than 10|
|8000||very distant future||over 30°|
|12000||ultramarket future||almost 45°|
The name, history and myth of the Little Bear
Known since ancient times, myths treat this constellation mostly together with the Great Bear. It was Thales, the Greek philosopher who lived in the 6th century BC, who introduced this asterism in the form of a bear in maps.
The Phoenicians saw in this constellation a coffin, that of a murderer, Al Jadi (the Polar Star), condemned to immobility for his crime. The coffin of the victim was seen in the stars of the quadrilateral of the Big Dipper, followed by the stars of the rudder that would represent the sons of Al Naash, the victim, in procession and in search of revenge, a story that is found also among the Arab populations, for which the North Star, and consequently extended to the whole constellation, was "the guide".
The ancient Egyptians associated with these stars the jackal, the god of chaos Suteck, then Seth.
In the East, among the Chinese, the same group of stars enclosed the image of the protectress of the navigators of the Taoist pantheon, Tou Mu, also known as the "goddess of the Polar Star", mother of the nine celestial sovereigns, represented sitting on a lotus flower, with three eyes and eighteen arms, and as many hands holding different objects, such as bow and arrows, the Sun, the Moon....; while Mongols called her "constellation of the magnet" because they were already aware of the instrument, and of the fact that her needle was oriented in that direction.
Starting with the Vikings, the vision of a small Chariot in the asterism is mentioned.
The German cosmographer Pietro Apiano (1495-1522) attributed to it an independent mythological relevance, seeing the Hesperides, the nine daughters of Atlas (Arethusa, Egle, Estia, Espera,Esperia,Esperusa and Eritea). In a vast and wonderful garden in the far west of the world, on Mount Atlas, they guarded and cared for the golden apple tree. Their myth is therefore intertwined with that of Hercules.
Another myth tells of Callisto, the beautiful daughter of the king of Arcadia, aroused the jealousy of Juno who turned her into a bear to eliminate her.
Arcade, Callisto's son, during a hunt, came upon his mother, but, not recognizing her in the bear, struck her wounding her.
Moved with compassion, Jupiter took the bear, and hurled it into the sky as the Big Dipper. Arcade was also transformed into a bear by Jupiter, a smaller bear that was placed in the sky near his mother to give life to the constellation Ursa Minor.
But according to Ploughed the Lesser Bear is one of the two nymphs of Crete who raised Zeus, Cynosura. In Greek Cinosura means "tail of the dog", with all probability its name is due to the fact that for the ancients the stars of the small Chariot, together with beta UMi (Kochab) and zeta UMi, remind the tail of a dog. It would be admissible since before the present identification, in this aggregate of stars one could see a dog's tail. If we think then to the bear, to its features, the long tail with which it is portrayed in the maps of the sky, appears completely erroneous, while if we think to a dog, the characteristic is completely justified. The English mathematician Thomas Hood, jokingly gave credit to the representations stating that the tails of the two bears had to be represented legitimately long, since they were taken by Zeus just for the tail, swirled and thrown in the sky. They were so long!
The depictions of the Little Bear
Let's see together how the constellation was represented in the Uranometria (strangely in this case the figure was specular and I had to straighten it)
by the astronomer Hevelius (this time the monster already upside down specularly, so with the illegible writing!).
and according to Stellarium
Before moving on to something else, it seems to me that in the image of Hevelius the bear is a bit chubby, while in the stellarium one it looks like a teddy bear with a very long tail...
We have come to the comparison of the biggest stars of the constellation Ursa Minor with the milestones we have encountered so far: clicking on this patchwork blanket we can see which and how many stars of Ursa Minor are so big to be compared to other known stars. Well here we really see so many stars overcoming the threshold of 30 times the solar ray (apart Pherkad and ε UMi, that I added as a color note) and above all overcoming those milestones that by now have become Rigel and Aldebaran.
Among the stars of the Lesser Bear I chose the biggest one, the variable star RR UMi, as a stage of my flight, enticed by the fact that the Errerreumidi are very good at making pizza with the strength of their eight arms. The star appears, from the usual distance of 10 UA, as a red flaming globe, very bright and big, so hot that the natives take just two minutes to bake the pizza, simply exposing it to the RR UMi.
Another dutiful stop, even if the star is not among the biggest, was instead Kochab, a beautiful yellow-orange star, 44 times our Sun: you must know that the Kocabbiani are skilled grape pressers with which they make an excellent green wine (the Verdello of Kochab). I guess you know that the grapes in this case have a radius equal to 23 times that of the Earth's grapes, but ... they are certainly not the largest grapes in the universe!
Constellation with few strange names
Let's get back serious and now let's see the few names of the few stars of the Lesser Bear: apart from the Polar, all the others are quite difficult and practically impossible to remember.
- Alruccabah (α UMi): it comes from the Arabic the knee, certainly not from the bear. It is the most indicated name for the Polar when it will no longer be the polar star.
- Kochab (β UMi): from the Arabic or Semitic star
- Pherkad (γ UMi): from Arabic the two calves
- Yildun (δ UMi): nice name, from Turkish origin meaning star
- Akhfa al Farkadain (ζ UMi): from the Arabic the weaker of the two calves
- Anwar al Farkadain (η UMi): from Arabic the brightest of the two calves
I have to say that I have never heard these last two names in over 40 years of Astronomy, so I would suggest that we forget them, especially the first of the two, a real tongue-twister. Naming two stars with two folkloristic and fascinating terms that mean "star" sounds a bit Lapalystic to me...
When can we observe the Little Bear?
The answer is very easy: always, at any time of the night and at any time of the year. Just look to the North and to a 'on the horizon equal to the geographical latitude of the point where we make the observation of the sky: there we will find the now famous Alruccabah waiting for us.