Capricorn is a zodiacal constellation that the ancients saw and recognized very well, while for us "citizens" it is particularly difficult to see because of the diffused light of our cities and the lack of bright stars, also because at our latitudes it never appears very high on the horizon. Let's also say that to see a Capricorn appear in a sort of triangle of stars it takes a lot of imagination: not even H.A.Rey had succeeded in doing so.
For now we see another image, as I always do for the zodiacal constellations, created by two single images of Stellarium: we can see first of all the constellation crossed by the red line, the ecliptic, which shows the path of the Sun during the year, particularly between the dates of January 20th and February 16th, in which the Sun crosses the boundaries of the constellation entering and leaving it. As always, I would like to emphasize that these dates are actual, real, which are repeated every year except for a small difference due to the irregularity of the Earth's motion around the Sun. And this is precisely the irregularity that possesses the apparent motion of the Sun on the celestial sphere: instead, the dates provided by calendars and other non-scientific sources have no correspondence with the sky and the motions of the Solar System.
The name, the story, the myth of Capricorn...
For Mesopotamians, Capricorn marked the day of the year when the Sun was at the southernmost point of the equator (winter solstice). The mythology of Capricorn as a goatfish could have Assyrian-Babylonian origins in the figure of Oannes, god of wisdom, half fish and half man, a singular figure that was said to emerge from time to time in the Persian Gulf in the form of a mermaid to teach mankind the arts and sciences. The Sumerians saw in this constellation, instead, the water god Enki, a hybrid being, a kind of ram with a fish tail.
Among Latin poets, Capricorn was known as Neptuni proles (the offspring of the god of the seas, Neptune).
In Indian constellation mythology it was a crocodile or a curious goat-headed hippo.
Apart from the theme of the goat-fish, Capricorn, the tenth zodiacal constellation and therefore of very ancient origin, is associated with the god of the mountains Pan (Priapus, in Asia Minor), Greek god protector of pastoral life and inventor of the homonymous flute, seen as a satyr, with human body and goat's horns and hooves. It is said that at the arrival of the sea monster Typhon, sent by Rhea to exterminate the gods of Olympus, he tried to escape by diving into a river and transforming himself into a fish, but his transformation would only take place halfway. So back on the mainland to face Typhon, who had already torn Zeus to pieces, he would have launched a scream so long that Hermes would have had time to track down the scattered limbs of Zeus. Defeated Typhon, the father of the gods would reward Pan, who had remained in his satyr-fish form, by placing him in the sky among the stars. In another version he warned the gods of the arrival of the monster Typhon, sent by Gaea. Another version claims that the gods were simply celebrating all together on the banks of the Nile. The gods deceived the monster by turning into various forms, while Pan tried to turn into fish, but this transformation was only partially successful, and Pan for this reason often represents half fish and half goat, i.e. Capricorn.
Capricorn this unknown
Now let's see how Capricorn was represented in Uranometry.
while here there is the created drawing of Hevelius, represented as if it were seen in the mirror
and finally how the Stellarium represents it.
Just a few more curiosities
I don't know very well the famous Jimi Hendrix: I was too young when he showed off his great guitar skills in the '60s. I discovered that a bootleg called "The Capricorn Tape" had been published in 1970 (the year he died), the cover of which is as follows
By a strange coincidence, in the same year the Post Office of San Marino had issued the well known series entitled to the Zodiacal Constellations, twelve stamps of increasing facial value, starting from Aries and ending with Pisces: Capricorn is the third in the list and therefore it had a value equal to 90 Liras, which for that time had a not indifferent value.
A few stars nearby
The constellation of Capricorn presents five stars whose distance from us is less than the threshold of 60 al. In the table we see listed these stars: in the first column there is the distance expressed in light years, in the second column there is the identification name with the link to the image taken from Celestia of how we can see the Sun from the parts of the star under examination, while in the last column there is the spectral class.
For example from the three stars HIP 99825 (a star of magnitude 5.7, therefore theoretically visible in our skies with the naked eye), from HIP 101997 and from ψ Cap, while from δ Cap is inside the constellation of Leo (or so).
A few big stars
In the usual diagram that accompanies us in each episode and in which I have traced the stars of Capricorn to compare their dimensions with other stars we have met in previous articles, we see that there are 6 stars of remarkable dimensions, but not of the star monsters we have met before.
The largest of the group, ω Cap, is 139 times our Sun, but the fact that it is of spectral class K4 puts it in the same family as His Majesty Aldebaran, with a diameter that is almost 4 times that of the well known Taurus star: my Omegacapi friends are very proud of this fact. Through Celestia I went near this star and photographed it from a distance of 10 UA.
Of the same family and therefore of the same spectral class, are 24 Cap and σ Cap, respectively 64 and 59 times our Sun and even in this case almost a couple of times larger than Aldebaran.
The second star in order of magnitude is instead 47 Cap, class M3, with a diameter that is 109 times that of the Sun: always with Celestia I took the picture of this red giant, the star of my friends Forty-seven chapters: they are famous in the galaxy to be skilled writers, with the peculiarity that all their books consist of 47 chapters, hence their name. For example, volume 12 of their Trecconi Encyclopedia (where the cone is their faithful quattrozampe) has 47 chapters, the famous yellow Il Codice Da Perdi has 47 chapters, but also their dictionaries have 47 chapters, since 47 are also the letters of their alphabet. Guess how many hours their planet's rotation time is...
But let's move on to more serious things, which is better.
Two not bad Deep Sky objects
Among the deep sky objects present inside the constellation, I have chosen two very interesting ones and of which I show the photo taken by HST (clicking on the photo we can see the enlarged version, with more details). Let's start with the object number 30 of the Messier catalogue, to the century M30, a beautiful globular cluster
the globular cluster M30
while in this other picture we see a beautiful crossed-out spiral galaxy, the NGC 6907...
the galaxy NGC 6907
The names of the stars
Let us now see the names of the stars of Capricorn:
- Giedi I,II (α1, α2 Cap): the goat
- Dabih Minor, Major (β1, β2 Cap): the butcher
- Nashira (γ Cap): the lucky one
- Deneb Algiedi (δ Cap): the goat's tail
- Castra (ε Cap): found on internet
- Yen (ζ Cap): found on internet
- Barm (η Cap): found on internet
- Dorsum (θ Cap): found on the internet
- Al Shat (ν Cap): the sheep
- Baten Algiedi (ω Cap): the belly of the goat
Even if it is a zodiacal constellation and precisely because of the low brightness of the component stars, the names actually used most commonly are those of α and δ Cap, while the others are just a curiosity.
The visibility of Capricorn
Taking as always an hour of reference, convenient for observations, 9 p.m., we have that Capricorn lies low on the eastern horizon towards the last days of July, while it culminates in the South, not very high in the sky, around the beginning of October. Finally it will be low on the western horizon more or less towards the beginning of the following December.