Sun in Medical Astrology

In the texts this site draws on, the Sun stood for the vital principle and, by day, for the native’s life itself. Ptolemy made it the first candidate for the prorogator, the point from which the length of life was measured, whenever a daytime birth set it in one of the places he allowed. Lilly, writing in 1647, called it a giver of life and put the heart and the eyes under it, and Culpeper repeated the heart in 1655. The Sun had no illnesses of its own in the sense a modern reader might expect: it was read for the strength or hindrance of the vital spirit, by its sign, its house, the planets it joined and the dignity it held. Everything on this page is that reading, stated as history, and none of it describes any living person.

The Sun keeps the most regular calendar of any planet in this series, and the table beneath this section is close to a calendar of the seasons. Over 1900 to 2050 the sample counts 1,812 sign entries, which comes to twelve in every year with no re-entries at all, because the Sun never reverses. Its mean stay in a sign is 30.4 days, a twelfth of the year to the day, and the stays are the twelve solar months that the sign pages for the 6th house describe one by one, each with the Sun’s entry dates for that sign.

The table is not perfectly flat, and the unevenness has a cause the old astronomers knew. The Sun spends the most days in Cancer, 8.61% of the sample, and the fewest in Capricorn, 8.06%. Its longest single stay runs 32 days, in Cancer. The apparent Sun moves slowest when the Earth is farthest from it, which at present falls in early July, and fastest in early January, so the northern summer signs take a day or two longer to cross than the winter ones. Ptolemy’s solar model carried the same inequality, with its slow point then in Gemini; that point has since drifted into the next sign.

The retrograde column reads 0% of days, and it reads that for a reason of geometry rather than sampling. Retrogradation is the apparent reversal of a planet seen from a moving Earth, and the Sun is the reference point against which the others are measured. The texts listed retrogradation among the debilities of the five planets, and the two lights were exempt from it by definition.

The table in this section sets the three sources side by side, as the site’s data file records them: Ptolemy’s chapter on injuries and diseases in the Tetrabiblos, Lilly’s chapter on the Sun in Christian Astrology and Culpeper’s chapter on the planets and the parts in the Astrological Judgement of Diseases. All three put the heart under the Sun, and all three put sight or the eyes there too. That is the whole of their agreement, and it is a large one: no other organ appears in every column of the Sun’s row.

The differences are additions. Ptolemy added the brain, the sinews and the right-hand parts, in keeping with a Greek scheme that gave the right side to the Sun and the left to the Moon. Lilly added the back and the vital spirit, and specified the right eye of a man, leaving the left to the Moon. Culpeper, writing for physicians, added the arteries, the vessels that carried the spirit in the physiology of his day. None of these entries contradicts another; each author named more of the same region or the same faculty.

The nature in the first column, hot and dry, is the humoral tag every text attached to the Sun, and it is the reason the diseases Lilly listed under it were the hot and dry ones. The Sun’s one sign, Leo, was listed on the Zodiac Man at the heart and back, so sign and ruler agreed about the heart. That agreement between the sign list and the planet list is set out further in the Zodiac Man guide and in the planets and the body guide, which reads all seven classical rows of this table together.

Ptolemy’s rule for the length of life began by choosing a prorogator, and the Sun was the first choice by day with one proviso: it had to stand in one of the places he allowed, the rising place, the midheaven, the eleventh, the seventh or the ninth. The 1st house qualified; the 6th did not. A daytime Sun in the 1st was therefore read as the native’s own life-point, judged by the planets that cast rays to it, while a Sun in the 6th handed the role to the Moon or to the Ascendant itself.

Lilly’s chapter on the Sun, like each of his planet chapters, opened with the person it described when it ruled the Ascendant or stood in the 1st house: the shape, the coloring, the manners when well placed and when ill placed. Those descriptions belong to the 1st house, the house of the native’s body in his scheme, and they were read as portraiture rather than as medicine.

The 6th house in Lilly was the house of sickness, servants and small cattle, and his method for a question about sickness drew its significators from the Ascendant, its lord and the Moon for the sick person, and from the 6th, its lord and any planet inside it for the disease. A Sun inside the 6th was therefore counted among the significators of the disease, read by its nature, hot and dry, and by the parts in the table above. Culpeper’s decumbiture method used the same houses. The 6th house guide sets out the whole house, its ruler and what the 1st, 8th and 12th added to it.

Steve Jobs’s chart is used here as a specimen of the method and for nothing else; nothing about the man enters the page. His Ascendant is Virgo, his 6th cusp is Aquarius, and the Sun stands in Pisces in the 6th house. He was born by night, which under Ptolemy’s rule put the Moon ahead of the Sun as the candidate for prorogator before the houses were even looked at; the Sun’s place in the 6th, outside the allowed places, would have excluded it in any case. The Moon, in Aries in the 7th house, stood in one of the places Ptolemy accepted.

In Lilly’s terms the Sun here is a planet in the house of sickness, a significator of that house’s matters alongside its lord, Saturn in Scorpio. Pisces is none of the Sun’s dignities by Lilly’s table, neither its house, its exaltation nor its triplicity, so the tradition would have called the Sun peregrine there. An astrologer of 1647 would then have gone to the aspects: what the Sun received from Saturn and Mars, and from Mercury, the lord of the Ascendant. The page stops where the method stops; the chart is a diagram of placements, not a statement about anyone.

Lilly’s table of essential dignities gave the Sun its house in Leo, its exaltation in Aries, its triplicity in the fiery signs by day, and faces in certain decans; it gave the Sun no terms, since the terms belonged to the five planets alone. Opposite those stood its detriment in Aquarius and its fall in Libra. The same table scored each dignity and debility in points, which Lilly summed before he judged, and a planet with no dignity at all in its place he called peregrine.

Combustion was a relation to the Sun, so the Sun could not itself be combust. Lilly set the measure at eight and a half degrees on either side of the Sun in the same sign, with a wider band for a planet merely under the beams and a very narrow one for a planet in the heart of the Sun, which he called cazimi and counted as a fortitude. The tradition read a combust planet as one whose signification was overpowered by the Sun’s light, and a planet so placed was read as hindered in whatever it signified in the chart. That is what the texts said it meant; this page does not say what it does.

Retrogradation the Sun never had. The sample’s figure, 0% of days, is the same for the Moon and for no other planet in this series. Lilly listed retrograde motion among the debilities of the five planets and scored it against them in the same table, and he read a retrograde significator in a question as a matter that went otherwise than expected. The texts had nothing to say about a retrograde Sun because there was none to see.

Under Placidus the 6th house is the stretch of sky just beneath the western horizon, so the Sun occupies it in the hours after sunset. Placidus divides each planet’s own arc beneath the horizon into thirds, and the Sun sits in the 6th for the first third of its night, which is to say one sixth of the night. The sample’s figure at forty degrees north is 1.91 hours a day, a little under the two hours that an even twelfth of the day would give. A winter evening at that latitude keeps the Sun in the 6th longer than a summer one; the small shortfall is what the sample happened to find, not a rule.

The share by latitude runs 8.34% at the equator, 7.98% at forty degrees north and 8.26% at sixty, and the Whole Sign figure at forty degrees north is 8.29%. All of these sit near one twelfth, which is what a planet that keeps to the ecliptic and circles the chart once a day is bound to do. The choice of house system matters for a given chart, where a Sun close to the cusp changes house, and hardly at all across the population of charts; the methodology page gives the sampling behind the table.

A Sun was never read alone in the texts. Lilly went first to the lord of the sign the Sun occupied, to see whether that planet received the Sun by dignity, and then to the aspects the Sun made to Saturn and Mars, the two he called the infortunes, and to Jupiter and Venus, the fortunes. A Sun joined to the lord of the 6th, or in square or opposition to it, was read with that house in mind. These were the texts’ rules of judgment, set out here as such.

The other pages in this series take each planet in turn with the same three tables, and the sign pages for the 6th house take the cusp sign by sign, with the Sun’s own sign, Leo, among them. The Moon page is the nearest companion to this one, since the two lights shared the role of giver of life and the exemption from retrograde motion. The planets and the body guide reads the seven classical rows together, and the 6th house guide reads the house that this page has only touched.