As it happens I do really like Doris Lessing, but have only read The Golden Notebook, The Grass is Singing, and This Was the Old Chief's Country, and have never managed to read any of her science fiction about Canopus in Argos.

Thank you for this clear explanation Hornblower. As I noted above I should not have let my enthusiasm get the better of me in postulating an impossible hypothesis. After my blooper in the OP you might not be interested, but I want to argue that the match between Canopus and the precession is not just numerology. There are long term cycles of the solar system, and the distance from Canopus to the Pole modulates these cycles.
The equivalent star for the North Celestial Pole is Vega, which like Canopus in the South is a very bright star that was at the Pole about 12,000 BC. At the time Indian astronomy calls the golden age, earth’s axis points to both Canopus and Vega. Matching the Golden Fleece myth of Jason and the Argonauts, Canopus and Vega are both ‘guarded’ by dragons – Scorpio and Draco – in their relation to precession of the poles, indicating how observation of the stars is embedded in mythology. As ever, this field of study is beset by unscientific claims. One interesting commentary is at http://www.sirbacon.org/mham.htm

Leaving aside the imaginative ideas about galactic scale gravitational harmonics, the diagram of the South Celestial Pole shows Canopus is closest to the pole when the March equinox point is in Virgo, around 12, 000BC = 14,000 AD, and furthest from the pole when the equinox point is in Pisces, around 500 to 1000 AD. Hence Canopus is a clear marker of the precession, but due to its southerly position, unseen to northern astronomers, and the slow period of the precession cycle, this long term pattern was only seen in India, and in the corresponding northern myths of the Finnish Kalevala in which the Sampo is the cosmic mill knocked off its axis.

The overlay of the Vedic Yuga and the Zodiacal Ages, indicated by the year numbers in the outer circle of my diagram above, provides two matching ways to measure the precession. The Yuga is based on the positions of Canopus and Vega, and its ascending and descending traditional interpretation matches the Ages based on the western zodiac signs. Scientifically, both Yuga and Age may seem arbitrary, but culturally both have a comparable claim about the structure of terrestrial time. My interest is to see how these mythological ideas could be grounded in real cyclic patterns.

The underlying ATM idea here is that the slow movement of the sun backwards through the signs of the zodiac has a cyclic inverse relation to the pattern of the sun’s annual path. This relation is modulated by Canopus and Vega as markers, but physically caused by the long term stability of earth’s gyroscopic wobble. The mainstream view is that there is no such material relation between the Great Year and the annual rhythm.

To illustrate the possible nature of such a relation, in the picture above I have denoted the zodiac ages by the themes which astrology claims for each of the signs. The premise is that the twelve themes of the zodiac signs describe the early, mid and late phases of the four seasons, as marked by the four cardinal points of the equinoxes and solstices and the derived mutable and fixed points.

Any such cyclic effect must be extremely weak, given the lack of statistical corroboration, but at least it is permanent and unchanging by human standards, built in to the original structure of life on earth. The twelve themes of the zodiac signs match the themes of the natural year from spring to winter. These themes, in order, are: be, have, think, feel, will, analyse, balance, desire, see, use, know, believe. These themes flow into each other in a logical emergent order which matches the annual cycle of the northern seasons. If the precession causes a deep slow rhythm in the long term complex systems of the earth, it is reasonable to postulate that the twelve ages as shown incorporate the same natural rhythm encoded in the annual cycle, in reverse.

The twelve ages of the zodiac, starting from belief (Pisces) through knowledge (Aquarius), around to having (Taurus) and being (Aries), can readily be interpreted against the ascending and descending motif of the Yuga. This effect is too weak for easy scientific detection, and can only be seen in the weak traces left in mythology, a cultural artefact which embeds the efforts of people over the millennia to ponder the stars.

Postulating a directionality to this cycle, we can ask if the Age periods match the sign periods. Indeed, there is a close match between the Yuga cosmology of the movement of Canopus and Vega towards and away from the Pole as ascending and descending phases, and the Zodiac Age themes, which ascend backwards through the signs of winter and autumn and descend through the signs of summer and spring.

Matching this zodiac precession cycle against the back and forth of Canopus against the Pole need only be a possible interpretation to justify an against-the-mainstream argument. The effect is too weak to be easily measurable, so the question is whether it is mathematically coherent.

The annual cycle of the seasons and the diurnal cycle of day and night are the main temporal structures for the earth. The seasons have been stable for as long as the earth has had a 23° tilt. Considering the earth as a gyroscopic satellite of the sun, it is reasonable to consider the pulse of this wobble as embedded in life.

The hypothesis then arises of a harmonic resonance between the apparent forward annual motion and the backward precessional motions of the sun. This hypothesis can be depicted by denoting the ages by themes as shown. I have no way to prove that these themes are meaningful except by reference to mythology, showing how this cosmology provides a way to interpret the evolution of culture, and by elaboration of a possible scientific-mathematical model, as in the diagram above.