Lunar nodes and sun eating dragons!

The plane of the lunar orbit is inclined to the ecliptic by 5.1°.

The ecliptic (marked in red) is the apparent path of the Sun over a year - so it takes the sun one year to complete the circle. Meanwhile the moon follows a similar path, completing it in one month. Because the paths of the sun and moon are at an angle to each other, the moon crosses the path of the Sun twice every month. These points of crossing are called, lunar nodes, and they move gradually westward, performing a complete circle around the ecliptic in approximately 18.6 years - which is known as a draconitic or nodical period.

Why is it a Draconic cycle?

There is an ancient idea of destruction and danger lurking in the sky. The older Egyptian Book of Gates, describes the solar journey through The Amduat. Every night the God Ra travels through the twelve gates to be rejuvenated and reborn. But the journey is always perilous and the Solar boat - the solar barque -  is in danger:

Hour 7: Regenerating the light of Ra is a very dangerous moment in the journey, as it attracts the forces of evil present in the underworld. In this hour, Apep swallows all of the waters of Nun in an attempt to stop the barque and kill Osiris through Ra once more, preventing the daily cycle of the sun. The goddess Isis places a magic spell upon the barque in order to allow it to continue traveling through the regions without the need for water. On the upper register, the enemies of Osiris are punished for their intent to cause him harm, and the lower register contains humanized depictions of the stars following Ra's path to the end of the underworld.

• Solar eclipses occur when a new Moon crosses a node that is in front of the sun.
  
• Lunar eclipses occur when full moon crosses a node directly opposite to the sun, and the earth's shadow turns the moon a coppery red..

Back to the dragons!

Apep is depicted as a serpent or a dragon. 

Tales of Apep's battles against Re were elaborated during the New Kingdom. Storytellers said that every day Apep must lie below the horizon and not persist in the mortal kingdom. This appropriately made him a part of the underworld. In some stories, Apep waited for Re in a western mountain called Manu, where the sun set, and in others, Apep lurked just before dawn, in the Tenth region of the Night. The wide range of Apep's possible locations gained him the title World-Encircler. It was thought that his terrifying roar would cause the underworld to rumble. Myths sometimes say that Apep was trapped there, because he had been the previous chief god overthrown by Re, or because he was evil and had been imprisoned.

The constellation Draco. 

Draco is interesting -it's movement as an indicator of equinox and solstice makes it a candidate for the origin of the swastika. A similar symbol of 12 sun-runes [+] was likewise subverted to become The Black Sun. This idea of a chthonic power came from the mind of a 19th century writer, Edward Bulwer-Lytton who wrote a hollow earth story, describing an underground sun, and the power of Vril (which hilariously became Bovril...) But the 'spinning' pattern bears a resemblance to Draco that I can't ignore, and there was once an idea that an eclipse was caused by a black star lurking in the outer regions -  Draco was implicated!

And finally - this has nothing to do with astronomy - but Frank Herbert (author of Dune) gave Giedi Prime a Black Sun to indicate a place devoid of colour, love and life, of death.

Arrakis is of course, in Draco.

And one more literary link - “Caput Draconis in Virgo" would mean that the ascending lunar node is in the constellation of Virgo.

Meanwhile the ascending and descending lunar nodes are called 'head' and 'tail', caput and cauda. Lucia Bellizia has a paper you can download that gives us more detail (link at end of quoted text).

We read in Vitali that ascending and descending nodes are also called Caput and Cauda Draconis: why this particular name? Which Draco is this? An excellent answer is given by Franz Cumont in CCAG, VIII, I p. 194, where he produces some of the Excerpta Ex Cod. 8 (Paris.2423), attributed to an anonymous twelfth-century astrologer. The Belgian archaeologist and philologist reports that "An old opinion widespread in almost all the regions of the world states that a huge draco (snake) lived in the sky, and devouring and hiding the Sun and Moon, was the cause of their eclipses. This celestial serpent is often mentioned by astrologers, who taught that the nodes of the Moon course, ie ὁ Ἀναβιβάζων (o Anabibázon) and ὁ Καταβιβάζων (o Katabibázon) are its Head and its Tail and told many wonders about the nature and on the motions of that fabulous creature". In the first of these fragments (Fo. 9: First discourse on Anabibazon) we read: "The Babylonians, ie the Chaldeans, call Athalia this pneuma (spirit) which has the shape of a snake with two heads and two tails and one of two heads (8), one in Libra and the other in Scorpio, and in the same way the tails too, one is in Aries in opposition to Libra, the other in Taurus, and they dominate the third part of the zodiacal circle, moving with an ascending motion, and starting its movement from thirty degrees of Libra, and then it moves again starting from the thirtieth degree of Virgo to Libra; the tail also moves into Pisces in the same way. Both the head and tail, stay in each sign nineteen months and seven days, the Babylonians limit the stop to nine months and seven days [..]; but it dominates with its two heads and two tails for its opposition on a sign and accomplishes its action in them, therefore, it always travels without delaying or decreasing, but it is rather a backward motion. And it is found to be the most evil of evil stars, Sagittarius and Gemini obey him, and in them it accomplishes the most serious evils and his head is the cause of many evils not so much as his tail" ." [+]

More links:

• Images.[+]
• Stories [+]
• The Dragon of the Eclipses - A Note. [+]
• The Pendragon star. [+]
• Mithraic link? [+]
• North nodes! [+]