Hermes Trismegistus. This is the doctrine that a single, true wisdom exists, which threads through all cultures, and which was known in antiquity. Leonardo explicitly acknowledged this tradition in his Notebooks, but as far as I know only with his cryptic statement "Hermes the Philosopher". There was a ferment of scientific discovery, and Leonardo was in the forefront of the new spirit of natural observation. As I have just pointed out, not only the windows but also the traditional symbols of the four evangelists indicate Christ surrounded by the zodiac. Although we have come to associate it with irrationality, the zodiac is an entirely natural phenomenon. Leonardo was noted for his skepticism, and it is highly likely that he was skeptical about many of the traditional fables of his day. So I think it makes perfect sense, bringing all this together, that Leonardo would have secretly depicted this traditional story as really a sort of parable for objective observation of nature, with the annual path of the sun as a depiction of the natural cycle of the earth.
Instead of trying to fit the stars of each constellation into the picture in a subjective fashion, try another method, one which I attempted to use in my assessment of 'Andrew/Capricorn'
1/ get someone else, or preferably many other people, who have not been exposed to your 'interpretation' to mark out where the most notable points of each Apostle are located.
2/ Average out the locations of those 'notable points' to reach a consensus.
3/ These averaged-out 'notable points' have a much greater chance of bearing a relationship to any intended arrangement that may have been included by Leonardo.
4/ Attempt to superimpose the individual stars of each constellation over these averaged-out 'notable points; this should be done in as many different ways as possible.
5/ Determine the best fit by measuring the distance between each averaged out notable point and the location of each star.
I am certain that this process would show that the correspondence you claim to have found is no more significant than chance; but unless you do carry out these steps (or some other similar method of removing your own personal bias) then the correspondences you claim to see cannot be considered scientific.
There you go again thinking you can read my mind: I make no claims as to what Leonardo's intentions really were, but your interpretation is stilted and conventional; other interpretations are possible: I think my interpretation put forward in good faith fits better with Leonardo's naturalistic inclinations. Is it necessarily true therefore? Of course not. It's probably just my imagination, but then again, so is yours, and there is no definitive test to prove that your or my or neither version is true. That is a fact you have yet to grasp.Originally Posted by Robert Tulip
You keep saying this, but the 12-month calendar that's come down to us is anything but natural. Heck, an ordinary deck of cards has more astronomical meaning than the 12 month calendar: 52 weeks--52 cards; 4 seasons--4 suits; 13 cards/suit--13 Lunar months/yr--13 weeks/season. Dividing the night sky into 12 30° slices is a mere artifact of the Babylonian 360° circle--it has nothing to do with astronomy. So yes indeed, under your interpretation you shoehorn Leonardo into several conventions, including starting with Aries. However, naturalistically Aries starts on April 19. On my version, it starts with Gemini, which really starts on June 20--the summer solstice, a natural starting point. If Leonardo incorporated the constellations at all, he would have done it naturalistically, and included all 13, and not be bound by the conventions of Roman emperors and Babylonian astrologers.Originally Posted by Robert Tulip
You see 4 groups of 3. I see 3 groups of 3 and 1 group of 4, for a total of 13. See, that's the real reason Leonardo put that big "V" between John/Mary, in order to clearly demarcate Jesus from them, and to include him with the group to his left....Originally Posted by Robert Tulip
I went through your "matches", and some of them have 50% of the stars falling on other bodies; your Leo is squashed beyond all recognition; you have radically resized Virgo and Taurus so that it impossible to see their shapes without a magnifying glass; you also have a "flip" or two mixed in there. Mine have none of these transformations. 6 out of 6 people on this thread who have commented on the two versions prefer mine.Originally Posted by Robert Tulip
Also, you say that Leonardo had to hide the purported astrological constellations so he wouldn't be burned at the stake; yet you point out numerous overt examples of astrological symbols in medieval cathedrals; so, apparently, according to you, astrology symbols weren't in fact controversial. So there's no point in hiding that. On the other hand, a secret message that Roman Catholicism is false (i.e., that Jesus Christ is not the way to eternal life because there is no life after death)--that is a message that's worth both the telling and the hiding. Your secret message seems to be "There is a season, turn, turn, turn, turn--repeat ad nauseum :yawn:"--a message so trite it's not worth taking the trouble to tell, nor necessary to hide.
Only in the Chinese, cartoon-copy version of the painting....Originally Posted by Robert Tulip
The true sting is the sting of doubt and disbelief as symbolized by doubting Thomas...Originally Posted by Robert Tulip
No, the first hint is the Jesus/Ophiuchus connection--an association that apparently goes back centuries. I am not surprised that this is news to you, however. The second, confirming hint is the natural observation that the Sun only spends 1 week in Scorpius, and thus Thomas's diminished space devoted to him in the painting.Originally Posted by Robert Tulip
I don't find this ironic at all. It's a very apt description of what's going on in this thread. Like I said above, I am not the one making unqualified claims of veracity about how a 500 year old painting should be interpreted.Originally Posted by Robert Tulip
Some follow-up comments:
1. At this point, we have Robert and Warren offering two variations on the same theme, which is using a modifed display of familiar, culturally noteworthy constellations as a pattern for the people in Leonardo's work of art. What they have in common is keeping the 12 Zodiac constellations in their ecliptic longitude sequence.
The different choices of starting points do not bother me a bit. For one thing, the positions of the equinox and solstice points, which are the familiar seasonal benchmarks, change relative to the stars over the millenia, and it would not be unreasonable to make associations with various historic eras, should Leonardo have wished to do so for whatever reason. Now let us suppose for the sake of argument that he really wished to link the stars to the people in the painting, but needed to disguise them to avoid charges of blasphemy or heresy. In addition to rotating, resizing and perhaps flipping them, he could add a modest layer of encryption by shifting the starting point. For all we know, there might be a cryptic key to such a shift right there in the picture, just waiting for someone with the right kind of imagination and visual skill to discover it.
Of the two variations, I find Warren's more appealing. It has less distortion, and it brings Ophiuchus, a mythical healer, into the mix. Since the leader of this group of 13 people was reputedly a healer among other virtues, that adds a nice touch to this exercise.
While it is perfectly reasonable to speculate on the possibility that Leonardo may have been thinking along similar lines, I stand by my opinion that it is not realistic to conclude that he must have done so in general, let alone the specifices that Robert is insisting on. Robert's posts since my last one have done nothing to shake me on this issue.
2. At the risk of sounding pedantic, I offer the opinion that when Robert refers to "structure of terrestrial time", he really is referring to "structure of terrestrial patterns of motion", which are analyzed mathematically as a function of time. These patterns are indeed periodic and give us convenient, culturally desirable benchmarks for timekeeing, but their magnitudes and proportions are peculiar to this Earth/Moon/Sun combination. Time is a universal concept that is independent of a particular location. If the Moon were enough closer to complete 16 phase cycles in a year, we might be using a 16-month calendar and inventing a very different Zodiac. Doing so would be of no consequence in fundamental timekeeping for exercises in physics and astronomy. The same cesium atomic clock would be fine.
I ran across this today....
Giants Fan Beaten At Dodger Game Likely Suffered Brain Damage
Stow’s relatives said they did not blame Dodger fans for the attack.
“My family and I just want to express that we have no animosity towards the people of Los Angeles,” said Erin Collins, Stow’s sister. “We’ve been received with open arms and love.”
Of the attackers, she said, “They weren’t true Dodger fans.”
ETA: This post specifically alludes to Strange's claim in #111 that Mr. Tulip commits the no-true-Scotsman's fallacy when writes the following in post #109:
That is, the reasoning seems to be as follows:...each section of stars actually can be placed on the person ... with each star that makes up that constellation fitting within the frame of that person." This is a simple and accurate observation, and I do not understand why you cannot see it. I think you [eburacum45] are not really looking.
RT: All unbiased observers can see the pattern I discerned.
EB45: I do not see the pattern.
RT: You are not a true unbiased observer.
Last edited by Warren Platts; 2011-Apr-08 at 10:32 AM.
At night the stars put on a show for free (Carole King)
All moderation in purple - The rules
The difficulty people are having in following the case I have presented in this thread reminds me somewhat of a Sudoko puzzle. At first glance, a hard Sudoko looks impossible to solve, but with careful precise logical analysis, it turns out to have just one answer.
For The Last Supper, the method to find its hidden template involves looking carefully and precisely at the detail of each figure to see how the star patterns of the ecliptic are embedded in the same order as we can observe in the night sky. If all thirteen figures in the painting can be shown to conceal the expected patterns, it involves a solution as unique as a Sudoku. Evidence of deliberate design is that the embedded figures appear in the same order as in the sky, in continuity with other sources that match the twelve apostles with the twelve signs.
For each figure, we need to look at the specific configuration and ask if it has been intentionally structured in that way in order to depict the naturally observable constellation shape.
From right to left, the analysis of the figures reveals the following correlations with the constellations of the ecliptic in order. Links are to Wikipedia star maps.
I have explained these simple and elegant direct correspondences in some detail because my earlier explanations were not clear enough. I hope that readers will examine the detail.
1. The constellation Aries has three main stars, in a bent line with angle about 150°, with ratios between the two segments of about 3:1. The first apostle, Simon, holds his hands forming this precise shape, with the right hand forming a short line and the left arm a longer line in the same ratios and angles as the three stars of Aries.
2. The constellation Taurus contains two main prominently visible star groups. The Hyades, centred on Aldebaran, form an isosceles triangle with angle about 40°. The Pleiades is a small cluster with about 6 visible stars. Looking for these shapes in the second apostle, Thaddeus, we see that his left hand is held with thumb and forefinger forming two lines at the same angle as the two longer sides of the Hyades triangle, with the thumb making a straight line and the fingers a curved line in exactly the same way as the asterism. Thaddeus’s right hand, placed in the same position relative to the left hand as the Pleiades is from the Hyades, has all five fingers forming a shape that matches the stars of the Pleiades.
3. The constellation Gemini contains two parallel lines of stars starting from the bright stars Castor and Pollux, known as the twins. The match of Gemini to the third apostle, Matthew, is particularly interesting in revealing how Leonardo used specific natural observation of the night sky as his template. Matthew’s arms form two parallel lines that match Gemini. But Matthew’s left hand is in the position of the star conventionally included as one of the horns of the bull Taurus, extending beyond the conventional boundary of Gemini along the ecliptic. So we can see that Leonardo did not just use traditional constellation boundaries in a mechanical way as his template, but looked for himself at the night sky and modeled the ecliptic stars as they are observed.
4. The fourth constellation, Cancer, is shaped like a cleft stick, with four stars, three of them on the circumference of a circle and one near the centre along the diameter through one star and through the midpoint of the other two. The fourth apostle, Philip contains this precise shape in the angle between the head and his arms.
5. The fifth constellation Leo, has the distinctive shape of the mane of the lion around the star Regulus at the base of the question mark (?), and a second group of stars at the lion’s tail around the star Denebola. The fifth apostle James contains these star shapes, although in the most concealed manner of the thirteen constellations in The Last Supper. His left hand is cupped like a question mark, forming the same shape as the group around Regulus, and his right hand matches the position of Denebola.
6. The sixth constellation Virgo, forms a rhombus with diagonal ratios of about 1:4, similar to the iconic shape of the Virgin Mary. Looking at the sixth apostle Thomas, we see his right hand pointing to the sky (perhaps as a clue to Leonardo’s observational source in the night sky?) exhibits this same rhombus shape, but shrunk much smaller than the relative size of the constellation. Again, like Taurus, we see that Leonardo used the main visible asterism, the rhombus shape, rather than mechanically using all the stars now classified as in Virgo. So the bright star β near Denebola is part of the official constellation of Virgo, but does not appear to be part of the asterism that Leonardo used as his template.
7. The seventh constellation, Libra, the scales, is shaped like a balance, with a central star as the balance point, and two stars on either side as the ends of the beam and the two trays, much like the traditional symbol of justice as a set of scales. Looking for this shape in the seventh apostle John, the first to the right of Jesus, we can readily see that his clasped hands are in the position of the balancing star, his elbows are in the positions of the two beam stars, and his shoulders are in the positions of the trays of the scale.
8. The eighth constellation, Scorpio, is among the most prominent and readily identifiable shapes visible in the equatorial night sky. The bright star Antares is at the heart of the scorpion, surrounded by stars that track along the south of the ecliptic in a curve easily identified as the tail and sting of the scorpion. In the Last Supper, we see that the apostles Peter and Judas cross over, with Peter standing to the right of Judas, but leaning across so his head is to the left of Judas. It is clear that Leonardo has used the constellation templates in the order of the apostle’s heads, Peter’s right arm curves in the same way as the curve of the tail of the scorpion, and he holds his sword in the exact same position as the sting of the scorpion. His left arm and head are in the position of the stars at the scorpion’s head. The head of Judas, in front of Peter’s heart, is in the position of the bright star Antares at the head of the scorpion. (Ophiuchus, the next constellation on the ecliptic, actually barely touches the ecliptic, and its official boundaries include much of the ecliptic that is actually closer to Scorpio. This means we should not expect to find Ophiuchus in The Last Supper.)
9. The ninth constellation Sagittarius is conventionally depicted as a teapot. In the sky Sagittarius is visible as a group of bright wide pairs of stars across the Milky Way. Looking to map this to the ninth apostle (in order of heads), Judas, sitting at the table with his money bag, we can readily see that he matches the stars of Sagittarius as follows: Right hand = ζ, right elbow =τ, right arm and shoulder = σ and φ, head =λ, left shoulder =δ, left arm = ε, left hand = η. Again, some peripheral stars are not part of the template. His arms are bent with exactly the same angles as the constellation.
10. The tenth constellation Capricorn forms an equilateral triangle. We see this shape in the angles of the triangle formed by the head and hands of Andrew, the tenth apostle.
11. The eleventh constellation, Aquarius, matches precisely to the eleventh apostle James. ε matches to James’ left hand, draped around Andrew. β matches his left arm, and the stars αγδλ match his body.
12. The twelfth constellation, Pisces matches the twelfth apostle Bartholemew. α, the knot joining the ropes that conventionally end in the two fishes, matches the knot in his robe at his shoulder. The lines of the ropes, appear in the same angle as the lines of Bartholemew’s right arm and the line from his shoulder to his left arm.
13. Jesus Christ, the central figure, matches to Pisces. His right hand shows his fingers in the same shape as the fish known as the circlet, his head is in the position of the knot star, and his left hand is the other fish. There is a wide convention associating Jesus with Pisces, for example with the Christian symbol of the fish. Pisces is also the location of the March equinox. The equation between Christ and Pisces surrounded by the twelve apostles matching to the twelve ecliptic constellations, shows strong continuity with earlier Christian iconography, for example in stained glass windows at the cathedrals of St Denis and Chartres in France, which depict Christ as lord of the cosmos together with the twelve signs of the zodiac.
Last edited by Robert Tulip; 2011-Apr-13 at 09:39 PM. Reason: typo: Thomas right hand
Only one problem, Mr. Tulip: your interpretation does NOT have the star patterns in the same order as the night sky. There are 13 figures and 13 constellations along the ecliptic, yet you omit Ophiuchus entirely, and you have Pisces twice!Originally Posted by Robert Tulip
My interpretation, on the other hand, includes all 13 constellations/figures in the same order as the night sky, starting from the summer solstice, rather than an arbitrary day in the middle of April. And as one of your unbiased friends noted, "And of course Ophiuchus marks out the galactic center and Jesus is placed in the center position of the scene..."
Sorry, but my interpretation is the more elegant fit IMHO. This is not to say that my interpretation is necessarily true and yours is false: however unfortunately, this blows your 99.9999999999% certainty figure out the window...
BTW Thomas's left hand is supposed to be a loaf of bread, remember?
The interpretation of this picture, however, has a very large number of solutions, and you think you have found the only one because you decline to see the others.At first glance, a hard Sudoko looks impossible to solve, but with careful precise logical analysis, it turns out to have just one answer.
Did you see my suggestion for removing any bias from this question? Find a statistically significant number of volunteers and get them to mark where the important points in the painting are, then try to match these important points quantitatively with your interpretation. These volunteers must not have been exposed to your interpretation at any point.
I am trying to persuade you that your interpretation is entirely due to your own bias- it has no basis in scientifically testable reality. Testing your hypothesis while removing any possibility of bias would be very hard, and the end result will almost certainly be disappointing.
In The Last Supper, Leonardo uses the widely established motif of Christ and the twelve apostles as symbols of the sun and twelve months of the year, symbolised by the signs of the zodiac. This is a theme that goes back to ancient mythology, for example with Horus and twelve followers in Egypt. The idea of having twelve months, rather than thirteen or some other number, approximates closely to the division of each of the four seasons in three moons. Seeing how this motif continued in Christian iconography, for example in prominent stained glass windows of major cathedrals, indicates an ongoing tradition that saw the symbolism of the twelve followers as representing the annual natural cycle of the earth.
While this tradition was suppressed by the orthodox denial of allegorical meaning, it is entirely congruent with the Hermetic outlook that was recovered by major thinkers in the Italy of Leonardo's day, and with which he was clearly familiar. For example, Marsilio Ficino (1433–99) was one of the most influential humanist philosophers of the early Italian Renaissance. Hermetic philosophy was a significant advance over the thought of the middle ages, because it sought to explain popular symbols by seeing them as representations of natural observation. Hermetic thought was an important staging post on the path to modern astronomy, and was keenly studied by major astronomers such as Kepler and Newton. Leonardo rejected the magical content of Hermetic thought, but in this painting and others (The Baptism of Christ, Saint Jerome), he used the Hermetic idea 'as above so below' to represent major popular symbols by their corresponding astronomical patterns.
If you study the explanations I have given of each apostle against the shape of their respective star maps, the fact is that it is quite easy to find each constellation embedded within the corresponding apostle. By portraying Christ as Pisces, Leonardo uses the actual position of the sun at the spring equinox, in a way that is entirely congruent with his use of the zodiac stars for the twelve followers, and with the traditional allegory of Christ as the Sun. Other explanations lack the elegance and parsimony of this account, especially considering its congruence with ancient secret traditions that had again become prominent in Leonardo's day, and with Leonardo's own focus on detailed observation of nature.No, my explanation is purely a result of systematic observation. If you could point to any one of the thirteen figures and argue that the precise angles of the corresponding stars do not appear in it in the predicted order, you would be able to argue that I am just biased. However, as I explained again in greater detail in my most recent post, all the figures prominently contain the expected patterns.your interpretation is entirely due to your own bias- it has no basis in scientifically testable reality. Testing your hypothesis while removing any possibility of bias would be very hard, and the end result will almost certainly be disappointing.
Wait a second. Earlier you had you had the spring equinox starting with Ares. Now it's Pisces. Which is it?Originally Posted by Robert Tulip
Also, there are more "secret" traditions than one can shake a stick at. There was never a consensus among the "ancients" about which zodiak sign belongs to which apostle.
Also, there aren't 12 "months" in a year. "Month" and "Moon" come from the same root word. Fact is, there are 13 Lunar months in a year. There is no astronomical significance at all to "12" other than it composed of the factors 2 * 2 * 3 and goes into 360 degrees 2 * 3 * 5 times....
Last edited by Warren Platts; 2011-Apr-14 at 08:31 AM.
1. Continuing with more refined iterations to prove the correspondence between the twelve apostles and the twelve signs of the zodiac, I have now taken the parts of the painting that correspond to each constellation and superimposed them on the constellation maps.
2. Continuing with more refined iterations to prove the correspondence between the twelve apostles and the twelve signs of the zodiac, I have now taken the parts of the painting that correspond to each constellation and superimposed them on the constellation maps.
Last edited by Robert Tulip; 2011-Apr-14 at 12:26 PM.
3. Continuing with more refined iterations to prove the correspondence between the twelve apostles and the twelve signs of the zodiac, I have now taken the parts of the painting that correspond to each constellation and superimposed them on the constellation maps.
Last edited by Robert Tulip; 2011-Apr-15 at 01:38 PM.
4. Continuing with more refined iterations to prove the correspondence between the twelve apostles and the twelve signs of the zodiac, I have now taken the parts of the painting that correspond to each constellation and superimposed them on the constellation maps.
That is not the case. You must attempt to remove your own preconceptions and biases, or there is no science involved.No, the situation here is analogous to the paradigm shift from geocentric to heliocentric cosmology.
The modern 'linear' mindset sees human history in terms of steady progress from primitive ignorance to advanced knowledge. The quite different worldview that informs the hidden message within The Last Supper sees ancient wisdom as having a deep understanding of the natural cyclic context for life, and understands time through the constant recurrence of natural cycles. So, the natural cycle of the year, through the months and seasons, provides the temporal framework for philosophy. This attitude was more suited to an agrarian society that was close to the soil and dependent on intimate understanding of the seasons for survival. Modern technology has allowed us to escape somewhat from this natural context that ultimately still governs agriculture and climate. The implicit message is that our imagined escape from how natural cycles enframe our life has brought a loss of real understanding.
Implicit in The Last Supper, as explicitly in the windows of Chartres Cathedral, the position of the sun each month governs a different task, and put together these describe the whole of life over the course of each year. In both, Christ sits as a central cosmic governing symbol. This framework helps to explain the old maxim 'as above so below'. At the time each year when the sun is passing through each zodiac constellation, specific tasks are always occurring in the unchanging round of agrarian society. This linkage between cycles of earth and cycles of the heavens are explained here in specific detail regarding the windows of Chartres.
The question of 'preconception and bias' here turns around whether this old mindset of natural cycles is legitimate. I have shown, in increasing detail, that the matches between the twelve constellations and the figures of the painting are precise and ordered. This is a matter of inductive science. As ever, inductive evidence requires a deductive explanation, and that is why I have focussed on the strong continuity between this explanation and older mindsets regarding the natural cycle of the year as the structure of time.
That seems to me to indicate that you are describing a subjective phenomenon, rather than an objective phenomenon.I am arguing that there is a significant change of mindset required to understand Leonardo's motivation for The Last Supper(...)
I am reminded of the N-Ray debacle, where a scientist was convinced he had discovered a new effect, but it was wholly subjective.
All your investigations into this matter simply reinforce your expectations; nothing anyone can do can possibly disprove them.His report on these investigations, published in Nature, suggested that N-rays were a purely subjective phenomenon, with the scientists involved having recorded data that matched their expectations.
That means that your ideas are unfalsifiable, and although they are interesting they cannot constitute proof.
The symbolism in Holbein's Ambassadors, and in every other renaissance picture that includes symbolism, is of a representative kind- a distorted skulll represents mortality, an astrolabe to represent the heavens, a globe to represent earthly power and so on. What is not present in that picture (nor in any other renaissance picture) is hidden geometrical allusions to astrology or astronomy. The heavens are certainly referenced in the Ambassadors, but through the depiction of astronomical instruments and -yes- an actual star map on the shelf. Not by the shape of the arms of the Ambassadors themselves.We cannot prove that Holbein's Ambassadors contains a distorted skull.
As I've suggested before, if the zodiacal figures were really there in the picture, Da Vinci would have added symbolic allusions to them.
This method can be used to compare shapes, but note that it is named after Procrustes, who was famous for cutting people's arms and legs off so they would fit onto his bed.
To do it properly you need to establish landmark points
and this should be done without reference to your own preconceptions of the shapes in this image (preferably by someone else, or maybe by computer analysis)..
Last edited by Warren Platts; 2011-Apr-15 at 07:29 AM.
nautical almanacs. Sidereally the first point of tropical Aries is now in Pisces, and will precess into Aquarius in a few centuries time.
That is not relevant to this thread. The apostles and Christ are drawn using the stars as an empirical template. I am not aware of any symbolic meaning linking the individual apostles to theories about their corresponding constellation. There is a widely known theory linking Christ to Pisces based on precession of the equinox, for example as discussed by Carl Jung in his book Aion.There was never a consensus among the "ancients" about which zodiak [sic] sign belongs to which apostle.
The moon completes twelve orbits in 354 days. With 29.53 days in a lunar month, there are 3.09 lunar months each quarter, or 12.36 per year. Blue moon explains there are 13 moons only 7 times every 19 years. Most years have twelve full moons.there aren't 12 "months" in a year. "Month" and "Moon" come from the same root word. Fact is, there are 13 Lunar months in a year.
I don't agree that we can be so definite about the absence of any astronomical significance in the number twelve, but that would be a significant sidebar in relation to this thread.There is no astronomical significance at all to "12" other than it composed of the factors 2 * 2 * 3 and goes into 360 degrees 2 * 3 * 5 times....
Warren’s depiction to mine, I specifically show how the hands of all thirteen figures, and six of the heads, match directly to the constellation shapes, with the precise positions of the stars forming the detail of the stance of the figures. This is simply not the case with Warren’s drawing, which he freely described as ‘a dealer’s choice’.Time is a universal concept, but it has specific structure on our planet. The year forms a main constant stable rhythm of life through the seasons, marked by the annual passage of the sun around the zodiac. Orbital stability means the year has a regularity that gives it a powerful role as the main marker of time, making hypothetical alternative models on other planets irrelevant to how we ordinarily understand time. For practical purposes, and especially in Leonardo's day when life was closer to nature, the calendar is a far more important structure of time than the exact atomic calculations used in modern astronomy.when Robert refers to "structure of terrestrial time", he really is referring to "structure of terrestrial patterns of motion", which are analyzed mathematically as a function of time. These patterns are indeed periodic and give us convenient, culturally desirable benchmarks for timekeeping, but their magnitudes and proportions are peculiar to this Earth/Moon/Sun combination. Time is a universal concept that is independent of a particular location. If the Moon were enough closer to complete 16 phase cycles in a year, we might be using a 16-month calendar and inventing a very different Zodiac. Doing so would be of no consequence in fundamental timekeeping for exercises in physics and astronomy. The same cesium atomic clock would be fine.
Leonardo’s intent, as I interpret it, was to use the conventional depiction of The Last Supper as an allegory for the fundamental question of how humanity relates to the natural universe. The main constant in this relation, grounded in a temporal sense of place, is that every year the sun moves between us and the same constellations, which each mark one month. It can further be argued that by using Pisces as his template for Christ, Leonardo places the main annual temporal structure within the larger temporal framework of the wobble of the axis, seen in precession of the equinox.
It is interesting to speculate why Leonardo would have chosen to use this natural symbolism of the year in his depiction of the archetypal story of betrayal captured in the moment of the accusation of Judas by Christ. Perhaps Leonardo is implying that just as ordinary perception (Judas) fails to see the true identity of Christ, so too our ordinary perception fails to see how the stars provide the eternal (or at least apparently constant) framework for our mundane cycles of time. Just as Christ was conventionally interpreted as a breaking of the eternal into the temporal, so too the regular pattern of the sun against the stars is a main natural indicator of how constancy surrounds the flux of life.