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The Backdrop
Young Galileo
Telescopic Observation
Science versus Scripture
The Trial
Notes & References
About the Author
Galileo's Horoscope

Galileo's Astrology, by Nick Kollerstrom

Dialogue Concerning the Two Chief World Systems, by Galileo. Click here to view online reproduction details
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Galileo's Astrology: Culture and Cosmos

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The Irrepressible Galileo Galilei, by Deborah Houlding

In physics Galileo is remembered for discovering the laws of failing bodies and motions of projectiles; in astronomy he is known for pioneering telescopic observation and, through this, discovering sunspots, the irregular surface of the Moon, the satellites of Jupiter, and the phases of Venus. Most of all, he is remembered for championing Copernicus' Sun-centred universe and prompting the split that freed scientific knowledge from the restrictions of spiritual belief. Imprisoned in old-age for repeatedly publishing his views, his name has become immortalised as an emblem of resistance against the oppression of Truth.

The Backdrop

Twenty-one years before the birth of Galileo, Copernicus published his theory of a Sun-centred universe, the first copy being delivered to him just hours before he died. The initial reaction was lame. Few scholars took the trouble to read it and those who did treated it as just another hypothesis. Faith and reason had indistinguishable boundaries at this time, with Aristotelian principles firmly established as the harmonious solution to planetary motion and theological beliefs. The Ptolemaic system, which saw the Earth as stationary at the centre of the universe, had never been seriously challenged. The backdrop of stars was perceived as representing God in its permanence and immutability; only the sublunar sphere encircling the earth was subject to change and decay.

Galileo was 8 years old when a notable event occurred to question this belief. The Danish astrologer Tycho Brahe recorded the appearance of a bright new star in the constellation Cassiopeia. Over a period of observation lasting 18 months, he noted how it first appeared brilliant enough to be seen in daylight, then dimmed and disappeared from sight. 'Tycho's Star' offered proof that the higher spheres of heaven were creative; but since Aristotelian philosophy underpinned all teachings, its significance mirrored the path of its brightness and soon faded from academic attention.

Young Galileo

This was the climate into which Galileo Galilei emerged to pioneer a new world system. Born at Pisa, Italy, on 16 February 1564, his father, Vincenzo Galilei, was a renowned composer who instigated his own revolution in the arts by disputing the current theories on the structure of music. Galileo's questioning attitude towards authority is presumed to be inherited from Vincenzo, who was no stranger to publishing challenging remarks such as the one that appears in a study on counter-point: "It appears to me that those who try to prove an assertion by relying simply on the weight of authority act very absurdly". [1]

Galileo received an excellent education at a monastery near Florence[2] and in 1581, aged 17, showed enough talent for his father to send him to the University of Pisa to study medicine. Though born into the ranks of lower nobility, the Galilei family struggled to make ends meet and were unable to afford the university fees. It was hoped that Galileo would secure one of 40 scholarships available.

In the second year he showed enough promise to discover that a pendulum of any given length swings at a constant frequency, which led to the invention of the 'pulsilogium', a medical device used for timing the pulse of patients. However, Galileo was already attracting animosity by his reluctance to accept the common philosophy and the scholarship was refused, forcing him to leave the university without attaining his degree. Naturally, biographers have looked upon this as an early resistance to his liberal ideas, though Arthur Koestler in his book, The Sleepwalkers, writes: "It is more likely that the refusal of the scholarship was not due to the unpopularity of Galileo's views, but of his person - that cold, sarcastic presumption, by which he managed to spoil his case throughout his life". [3]

Excluded from university life, Galileo tutored privately and managed to maintain his studies. He developed his interest in mechanics, writing treatises on his inventions which he circulated in manuscript. Another early invention was a hydrostatic balance which attracted the attention of a number of scholars, one of whom, Marchese Guidobaldo del Monte, befriended Galileo and began a chain of recommendations that brought him to the attention of Ferdinand de Medici, the Duke of Tuscany. In a rather ironic twist of fate the Duke was so impressed with Galileo that he appointed him as a lecturer at the university which four years earlier had refused his scholarship. Just three years on, aged 28, he rose to the position of Chair of Mathematics at the esteemed University of Padua, where he remained until 1610.

Over the next 18 years Galileo established a reputation for his lectures, mechanical inventions and treatises, and remained free from major controversy. He had an affair with a woman of the Venetian lower class, Marina Gamba, who gave him three children, two girls and a boy, between 1600 and l606.[4] During this time he developed theories on heliocentricity but refrained from publishing them, fearing them likely to attract ridicule. He was to reach the age of 46 before making any open comment on his views, but his private correspondence shows he was convinced of the Copernican argument from the start of his academic career.

In 1597, Galileo was to receive his first contact from Johannes Kepler, then aged 26 and employed as Professor of Mathematics at Grantz in Austria. Kepler had completed The Cosmic Mystery, a treatise which expressed arguments in favour of Copernicus' Sun-centred universe. He sent a copy as a gift to the Chair of Mathematics at Padua, anxious for academic feedback. Galileo replied immediately, and wrote in cordial terms:

"I indeed congratulate myself on having an associate in the study of Truth who is a friend of Truth. For it is a misery that so few exist who pursue the Truth and do not pervert philosophical reason.... I adopted the teachings of Copernicus many years ago, and his point of view enables me to explain many phenomena of nature which certainly remain inexplicable according to the more current hypotheses. I have written many arguments in support of him and in refutation of the opposite view - which, however, so far I have not dared to bring into the public light, frightened by the fate of Copernicus himself, our teacher who, though he acquired immortal fame with some, is yet to remain to an infinite number of others (for such is the number of fools) an object of ridicule and derision. I would certainly dare to publish my reflections at once if more people like you existed; as they don't. I shall refrain from doing so." [5]

Although Kepler replied, imploring him to take a different stance and air his views, Galileo ignored his letter and ended the correspondence. It was 16 years before he would produce the first public indication of his beliefs; throughout the interim he continued to teach, and appeared to endorse the traditional Aristotelian arguments that the Earth did not move.

The reasons for Galileo's hesitation were based more upon the fear of ridicule than persecution. Scholars were not forbidden to discuss alternative cosmological theories, but unless physical proof was provided it was deemed inappropriate to speculate upon their relevance or to present them as 'Truths'. Galileo knew that although heliocentricity offered a more elegant explanation of planetary motion, he had no means of proving it. The instruments available at the time were not sophisticated enough to register stellar parallax [6] , one proof of the Earth's motion, and against this the physical senses perceive the Sun to rise and set around the Earth. As part of his duties Galileo was obligated to teach the traditional arguments that if the Earth were to rotate it would disintegrate and the clouds would be left behind, that things fall to the Earth because it is the centre of the universe, suspended and unmoving because the exterior of the universe is equidistant on all sides, etc. He realised that to seriously contradict a theory that had the benefits of time and human experience, he needed verifiable proof. This he was never able to provide, and another century was to pass before advanced technology and Newton's theory of Gravitation could combine to uphold heliocentricity scientifically. Galileo remained convinced, however, that tangible evidence was within his reach and the invention of the telescope in 1608 gave him the inspiration and motivation to pursue his quest.

Telescopic Observation

Galileo did not invent the telescope. According to his own report, it was after reading of a Dutch invention that he set to work to construct an instrument along the same principle. In August 1609 he invited the Venetian senate to inspect his own 'spy-glass' which, through a combination of a convex and concave lens, was able to magnify objects nine times greater than normal vision. The senate was greatly impressed, particularly by his suggestion that in matters of defence it would enable them to see the sails of ships two hours before they could be seen by the naked eye. When he presented his spy glass to them as a present they expressed their appreciation by doubling his salary to a thousand scudi a year and guaranteeing his position at Padua for the rest of his life. No doubt he felt some embarrassment when local spectacle makers were soon able to replicate his instruments for just a few scudi, but he committed himself to improving the power of his instruments and began to turn his attention to the heavens.

In March of the following year, 1610, he published Sidereus Nuncius, the 'Messenger of the Stars', which revealed the fruits of his observations. The tract was kept deliberately short in order to make it widely accessible and the style of language was uniquely devoid of philosophy. Combined with explosive contents, it made a remarkable impact worldwide. He wrote about the surface of the Moon, dismissing the common view that it was perfectly smooth, and describing it as full of lofty mountains and deep hollows. He wrote about the fixed stars, and told how he had witnessed "other stars, in myriads, which have never been seen before, and which surpass the old, previously known stars in number more than ten times". Most importantly, he wrote of his discovery of four new planets, the Moons of Jupiter which had never been imagined before. With this, he justified his first ever 'outing' of his heliocentric beliefs, writing:

"Moreover, we have an excellent and exceedingly clear argument to put at rest the scruples of those who can tolerate the revolution of the planets about the Sun in the Copernican system, but are so disturbed by the revolution of the single moon around the earth while both of them describe an annual orbit around the Sun, that they consider this theory to be impossible."

Although Galileo here offered support to the Copernican argument, it showed no commitment on his part. He was not stating that the system was correct, but that it need not be considered impossible. In fact nothing he suggested could be taken as evidence that the Earth was in motion, and even if Jupiter was shown to be revolving around the Sun, this could be adequately explained by the suggestion offered by Tycho Brahe that all the planets beyond the Moon are in composite motion around the Sun, which itself revolves around the Earth. [7]

The year 1610 was the crowning highlight in Galileo's career. His name became celebrated throughout the world and he was elevated to a new post as 'Chief Mathematician and Philosopher' to the Medicis. His relationship with Marina Gamba ended at this point and he left for Florence without her. [8] Later in the year he was to make two other important discoveries, one of which offered indisputable evidence that Venus revolves around the Sun, and not the Earth.

Naturally, Galileo was not the only person with access to a telescope, nor the only one making new discoveries. Thomas Harriett of Oxford had been making maps of the Moon by the aid of a telescope in 1609, before Galileo, but because Galileo was the first to publish his findings he established the principle claim. Dispute was arising fast over who should take the glory for these new discoveries, and Galileo became aware of the dilemma between the urge to publish his findings quickly, and the need to continue observations until certain of their accuracy.

His solution was to send communications in code to the Tuscan Ambassador in Prague. In that way he was not giving away his secrets, but could evidence the timing of their occurrence. In August 1610 he sent the following communication which he asked to be relayed to Kepler:


Kepler worked hard to solve the puzzle and concluded that the term was an anagram for a Latin verse to state that he had discovered a Moon around Mars. "Salve umbistineum germinatum Mania proles - hail, burning twin, offspring of Mars". In fact the answer was: "Altissimum planetam tergeminum observai - I have observed the highest planet [Saturn] in triplicate form".

It would be another century and a half before telescopes were powerful enough to establish Saturn's rings, but Galileo had become aware of its distorted outline and assumed the presence of two small moons on opposite sides. In September he sent another anagram which translates as: "The mother of love [Venus] emulates the shapes of Cynthia [the Moon]".

He had discovered that Venus showed phases like the Moon which, from the way that they appeared to Earth, could only be explained by its revolution around the Sun. The Ptolemaic theory of all the planets encircling the earth could now be disproved once and for all.

Initially, many of Galileo's assertions were disputed by scholars unable to witness the events for themselves. In a short time however, Jesuit astronomers were able to confirm his findings and the Church was ready to accept the abandonment of the Aristotelian cosmological view, if not its philosophical principles. The question now was whether Copernicus or Tycho was correct. Under the Tychonic system the Earth remained fixed, central and motionless; the Copernican system gave motion to the Earth, a fundamental contradiction of Aristotelianism. The Church took the view that, unless it could prove otherwise, science should support tradition. No-one was prevented from discussing the implications of Copernicanism in scientific terms, provided they refrained from using it to undermine philosophical teachings.

Science versus Scripture

Had Galileo been careful to avoid controversy in such matters, he could have rested upon his laurels and left the changing atmosphere of the times to filter through in a natural course. But despite his rise to popularity and favour in certain quarters, Galileo was also beset by critical challenges to his work, many of them edged with the ridiculing undertones that he had always despised. With the demolition of Ptolemaic cosmology achieved, he was eager to answer each and every critic and began to push harder in support of the Copernican revolution. Since the main drawback against its acceptance was the fact that it contradicted scripture, his answers to the objections were inevitably couched in language that subtly questioned the scriptures it was supporting.

In 1613 the rot began to set in. Galileo became aware of an after-dinner discussion involving, amongst others, the Dowager Duchess Christina and a professor of Mathematics at Pisa, Father Castelli. The Dowager had questioned Castelli over the new discoveries taking place, and whether he believed them to be fact. The way that it was reported to Galileo was that Castelli had assured the Dowager of their truth, adding only that the motion of the Earth remained unbelievable "in particular because Holy Scripture was obviously contrary to this view".

Galileo's response to the report was a published Letter to Castelli which was expanded and published a year later as Letter to the Grand Duchess Christina. It was an opportunity for Galileo to argue that science need not be tied too rigidly by Holy Scripture. It also implied that the Copernican system should be taken as a fact unless anyone could prove it to be false:

"Hence in expounding the Bible, if one were always to confine oneself to the unadorned grammatical meaning, one might fall into error. Not only contradictions and propositions far from true might be made to appear in the Bible, but even grave heresies and folliesÂ…. if truly demonstrated physical conclusions need not be subordinated to biblical passages, but the latter must rather be shown not to interfere with the former, then before a physical proposition is condemned it must be shown to be not rigorously demonstrated - and this is to be done not by those who hold the proposition to be true, but by those who hold it to be false."

The unspoken implication is that the Copernican system is a 'truly demonstrated physical conclusion' which the Church should realise, or accept the responsibility for disproving. To some, in particular Galileo's opponents, this was seen as a dangerous challenge to the authority of the Church, whose attitude had been to accept and readjust theological teachings as and when scientific advances had disproved them beyond doubt.

The Letter to Christina played into the hands of Galileo's enemies. As copies were circulated the contents became distorted and prejudiced by rumour. Clergymen, many of whom knew nothing of Copernicanism, were incensed at reports that the Church was being forced into a position of changing its views on the basis of unproved speculation. In outrage, the Bishop of Fiesole demanded that this Copernicus whom Galileo was defending should be instantly imprisoned, unaware that he had been dead for 70 years.

Considerable pressure was put on the Church authorities to act; to censure the document and admonish Galileo, but their own investigations into the matter concluded that in the context of Galileo's work his comments has not been unduly blasphemous. No charges were formally pursued but Galileo was warned privately to be wary of dabbling in matters of scripture; to write freely on his Copernican theory, but to remember to treat it as no more than a hypothesis.

By this stage Galileo was no longer content to remain silent or discreet. He continued to apply pressure on his contacts in ecclesiastical positions to help him achieve a review of Copernicanism and scripture. After a long series of private correspondence and informal reports on official researches into this matter, he requested an audience with the Pope, against the advice of all of his intermediaries who, knowing the intolerant attitude of Pope Paul V Borghese, realised the potential conflict that would be brought to a head. They failed to persuade him to desist, and in 1616 Galileo induced Cardinal Orsini, a youth of 22, to apply to the Pope for an audience. A report on the affair, written to Duke Cosmo II of Tuscany, reveals the sensitivity that was apparent to all except Galileo himself, and explains the subsequent unfolding of events:

"Galileo has acted more on his own counsel than of that of his friends. The Lord Cardinal del Monte and myself, and also several cardinals from the Holy Office had tried to persuade him to be quiet and not go on irritating this issue. If he wanted to hold his Copernican opinion, he was told, let him hold it quietly and not spend so much effort in trying to have others share it. Everyone fears that his coming here may be very prejudicial and that, instead of justifying himself and succeeding, he may end up with an affront.

As he felt people cold towards his intention, after having pestered and wearied several cardinals, he threw himself on the favour of Cardinal Orsini. The Cardinal then last Wednesday spoke to the Pope on behalf of Galileo. The Pope told him it would be well if he persuaded him to give up that opinion. Thereupon Orsini replied something, urging the cause, and the Pope cut him short and told him he would refer the business to the Holy Office."[9]

As a result, the Pope instructed the Qualifiers of the Holy Office to meet and form an official opinion on two propositions:

1) The Sun is the centre of the world and wholly immovable of local motion.
2) The Earth is not the centre of the world, nor immovable, but moves as a whole, also with a diurnal motion.

Their decision was that the first proposition was: "foolish and absurd, philosophically and formally heretical inasmuch as it expressly contradicts the doctrine of Holy Scripture" and the second was held to "deserve the like censure in philosophy, and as regards theological truth, to be at least erroneous in faith".

By use of the word 'heretical' the Holy Office had expressed its opinion in the strongest of terms. Due to the intervention of more enlightened cardinals, the verdict was moderated to a final decree which removed this word and merely reinforced the former attitude with emphasis. In short they were reaffirming that the principles of the Copernican theory was opposed to Holy Scripture and, whilst hypothetical discussions and explanations of it were permissible, its representation as a Truth was not.

Two days after the meeting of the Qualifiers, the following account of its implications to Galileo was recorded in the Inquisition files:

"His Holiness has directed the Lord Cardinal Bellarmine to summon before him the said Galileo and admonish him to abandon the said opinion: and in case of his refusal to obey, that the Commissary is to enjoin on him, before a notary and witnesses, a command to abstain altogether from teaching or defending his opinion and doctrine and even from discussing it: and, if he do not acquiesce therein, that he is to be imprisoned". [10]

Documents relating to this meeting suggest that Galileo accepted the decision without resistance - and was therefore not prevented from teaching, defending or discussing his opinions as he would have been had he refused. He later received a short and formal reception with the Pope, obviously not under the circumstances he had originally desired.

The Trial

For the next seven years Galileo kept a relatively low profile, complaining bitterly in private about "the ignorance, malice and impiety of my opponents who have won the day". [11] In 1623 events appeared to turn in his favour when Pope Paul V died and was replaced by the more liberal-minded Pope Barberini - one of the cardinals who had helped moderate the Qualifier's decree to remove the implications of heresy. In 1626 Galileo and Barberini met on several occasions and enjoyed a healthy friendship. The Pope encouraged him to forge ahead in his plans to produce a new manuscript which could explore the cosmological systems in greater depth. The Pope reaffirmed that, provided Galileo avoided theological arguments, he would meet with no resistance. Galileo urged Barberini to revoke the decree of 1616 entirely, but this he refused to do, instead suggesting that Galileo could consider the argument that although a hypothesis appears to work satisfactorily, this does not mean that it is true, since God may have produced the phenomena by some means which is beyond the understanding of mankind.

Galileo's Dialogue on the Two Chief World Systems was completed in 1630. It took the form of a dialogue between three characters: Salviati, a brilliant philosopher, who speaks for Galileo; Sacredo, who takes a neutral, questioning stance, and Simplicio a good natured simpleton who argues for Aristotle. Salviati and Sagredo had been friends of Galileo in real life, both of whom had died young.[12] Galileo claimed that the character of Simplicio was based upon Simplicius, a 6th century commentator on Aristotle, but the insult to the Aristotelians was blatant.

The book discussed the Ptolemaic and Copernican hypotheses in relation to the physics of tides. It took two years to appear in print due to bizarre circumstances which prevented it from being properly vetted prior to publication. The Chief Censor, Father Riccardi, was aware that the Pope had given approval and encouragement for the project, yet he was uncomfortable with many passages that he felt contradicted the 1616 decree. Deciding that the intricate nature of the subject was beyond him he passed the task to a Father Visconti, who struggled with the context of certain passages for a time, eventually came to a similar opinion, and passed it back.

Under pressure to release this long awaited work, the Censor made a deal to allow a license for the book provided that each page was properly approved by a more suitable academic, Prince Ceci, before being delivered to the printer in Florence. Soon after the licence was approved, Prince Ceci died, plague erupted in Rome and communication with Florence became severely hampered. Galileo, aided by the Tuscan Ambassador, demanded that a new censor should be found in Florence and a long series of negotiations ensued to establish an alternative to Galileo's liking. Riccardi eventually gave in to demands and the manuscript was prised from his hands with extreme reluctance: he gave in 'dragged by the hair', as the Tuscan Ambassador put it.

In February 1632 the first copies began to appear. The Holy Office immediately realised that Galileo had taken far too many liberties and the Pope was particularly offended because he was concerned that Galileo had intended the dim-witted Simplicio as a caricature of himself. It was Simplicio who voiced the lame explanation suggested by the Pope that some of the workings of God are beyond the comprehension of mankind - when he does so the other two characters remain silent, then decide to go and enjoy some refreshment in a gondola. By August the book was confiscated and in October Galileo was summoned to Rome by the Inquisition to stand trial for 'grave suspicion of heresy'. Three years after his trial, Galileo was to write, regarding the Pope's anger:

"I hear from Rome that his Eminence Cardinal Antonio Barberini and the French Ambassador have seen his Holiness and tried to convince him that I never had the least idea of perpetrating so sacrilegious an act as to make game of his Holiness, as my malicious foes have persuaded him, and which was the primary cause of all my troubles."[13]

At the trial it was maintained that Galileo had been commanded in 1616 not to discuss Copernicanism, either orally or in writing, which records show was not the case. Galileo was even able to produce a certificate signed by the admonishing cardinal of the time, proving that he had been subjected to no more restriction than any other citizen under the 1616 edict. Nevertheless, the Inquisitors maintained that he had not restrained himself to discussing the Copernican theory as a hypothesis, but that he had taught it as a 'Truth' and referred to those who did not share his views as 'mental pygmies', 'dumb idiots', and 'hardly deserving to be called human beings'. [14]

During the course of the trial the Pope's brother, Cardinal Francesco Barberini, spoke to him in private, and after "many, many arguments and rejoinders" persuaded Galileo to offer a confession in return for leniency. Now seventy years of age, he was interrogated under threat of torture but steadfastly declared that since 1616 he had been assured of the wisdom of the authorities, and had ceased to hold any doubts as to the indisputable opinion of Ptolemy on the stability of the Earth.

On 22 June he was found guilty of teaching that the Earth moved, compelled to abjure, and imprisoned for life, a sentence that was swiftly commuted to permanent house arrest. The Dialogue was ordered to be burned, and the sentence against him was to be read publicly in every university. [15]

According to the Tuscan Ambassador, Galileo returned from Rome "more dead than alive". [16] In 1637, aged 73, he lost the sight of both eyes but managed to complete a final work, Discourses Concerning Two New Sciences, which was published in 1638. This refines his earlier studies of motion and the principles of mechanics.

Galileo died at Arcetri, near Florence, on January 8, 1642. In that same year Newton was born and would carry forward the torch of knowledge by uniting Kepler's Planetary Laws with Galileo's mathematical physics to perfect the Law of Universal Gravitation, the missing link in the Cosmic Puzzle that was to establish heliocentricity beyond doubt.

An investigation into Galileo's conviction, calling for its reversal, was opened in 1979 by Pope John Paul II. In October 1992 a papal commission acknowledged that Vatican records showed Galileo had not been restrained from teaching or discussing Copernicanism in 1616, as maintained at his trail, and admitted the Vatican's error.

Galileo's drawings of Saturn and the phases of Venus

Notes & References:

  1 ] F. Sherwood Taylor, Galileo and the Freedom of Thought; London, 1938, p.1

This assumption accords with Galileo's nativity (see below), with Mars, ruler of the 4th house of 'the father' prominent in the 10th house of professional achievements and applying first to the conjunction of Neptune, and then to the square of the Sun and opposition of Uranus, itself in the 4th.

Literally, this denotes a prominent father of a strong and idealistic temperament, while psychologically it depicts Galileo's fierce assertion of deep-rooted visionary principles in the professional arena, as well as the troubles and conflict that arise as a result.

The Moon is exalted on the midheaven, the signature of someone whose very being identifies with their vocation and accomplishments. It is the indication of great public success, but through its rulership of the 12th house of 'self-undoing', also reveals the personal torment and feeling of restriction that Galileo experienced throughout his career. This was a life-theme, manifest at the end of his life through imprisonment, but ever present in the sense of limitation and frustration that accompanied the restriction of his ideas.

Galileo's nativity

The above is one of the charts that have been used for Galileo. For detailed information on his chart - as deduced from his own notes - see and Nick Kollerstrom's excellent article Galileo's Astrology.
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  2 ] The 3rd house cusp, showing the conditions of early education, is ruled by Venus, also exalted and strongly dignified; in trine to Saturn in the 12th.

Other charts have been proposed for Galileo but recent research into his own astrological charts and papers has revealed the one given here as the most likely. For further details and discussion see Interface by Nick Kollerstrom; 1997; Ascella Publications; pp. 33 and 84-86, and Nick Kollerstrom's highly informative article Galileo's Astrology
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  3 ] A. Koestler, The Sleepwalkers, 1959; republished by Penguin Arkana; p.360

Unaware of the relevance to his nativity, Koestler paints a picture of the physical attributes of young Galileo that perfectly accord with his Leo ascendant and Taurean Moon on the Midheaven: "His early portraits show a ginger-haired, short-necked, beefy young man of rather coarse features, a thick nose and conceited stare".

Looking beyond the arrogance that Galileo manifested outwardly, the strong emphasis on Pisces, Cancer, and the 8th and 12th houses, suggest a deeply reflective disposition, with strong emotional impressions and forceful ideals that contribute to a sense of alienation. No doubt gentler aspects of his disposition were masked by his stubbornness and fixity. The Sun conjunct Pluto shows great purpose and will - projected into the sextile that the Sun makes to his elevated Moon, Galileo would be inclined to obsession regarding his reputation and esteem. That the Moon is the ruler of his 12th house of misfortune, imprisonment and self-undoing, is by no means inappropriate.
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  4 ] This fact was provided by Gratzia Mirti, editor of Linguaggio Astrala, in her article 'The Astrological Work of Galileo'. Mirti has done considerable research on Galileo in recent years to prove that he was a practicing astrologer - a fact often overlooked in most biographical studies.
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  5 ] Koestler, p.362
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  6 ] David Plant explains stellar parallax in his artiche 'Tycho Brahe: a King Amongst Astrologers':
"Parallax is the apparent shift in an object's position against the far background when it is viewed from different foreground locations. As a simple demonstration, hold up your thumb at arm's length and see it move when you hook at it first with one eye covered, then the other. Tycho reasoned that if the Earth were in motion around the Sun then the nearer stars should show parallax against the more distant stars as the Earth moved through different points on its orbit. His reasoning was correct, but even Tycho's marvellous instruments were not accurate enough to register stellar parallax given the vast distances involved."
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  7 ] Brahe's theory was not entirely original, but extended earlier classical propositions by Pythagoras and Herakleides which fell from favour because they contradicted the physical senses.
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  8 ] At this time his midheaven-ruler, Venus, was by primary direction at 7 degrees Taurus, conjunct his 10th house Moon and in a partile sextile to the Sun, his ascendant ruler.

On the departure from his family Nick Kollerstrom writes in Interface (ch.4, p.33):

"Galileo drew up charts and interpretations for his two daughters, Virginia amid Livia, which still remain. In 1613, when they were 13 and 12 years respectively, he placed them in a monastery for life, as they were too expensive to maintain. The first monastery he approached refused, on the grounds that they were too young, so he found another! They remained devoted to their famous father."

It is likely that the desire to place his daughters in a monastic environment was more than the need to offload an expense since in Galileo's nativity, Jupiter, ruler of the 5th house of children, is located in the 12th.
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  9 ] Quoted in Koestler. p.461
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  10 ] Ibid., p.468
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  11 ] Ibid., p.471
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  12 ] N. Kollerstrom, Interface; 1997; Ascella Publications; Ch.4. p.34.
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  13 ] V. Gebher, Galileo Galilei and the Roman curia; 1879; op.cit. p.161
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  14 ] Koestler, p.493
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  15 ] Nick Kollerstrom, in his book Interface writes (p.37):
"On this ruinous day, whose shadow reached with such grave consequence into future centuries, the two malefics Mars and Saturn stood in exact opposition (2' orb), with Mars conjunct Galileo's own Mars (1°)."
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  16 ] Koestler. p.496
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Deborah HouldingDeborah Houlding is the web mistress of the Skyscript site. The past editor of The Traditional Astrologer magazine, and author of The Houses: Temples of the Sky, her articles feature regularly in astrological journals. She has a particular interest in researching the origin and development of astrological technique and as a consulting astrologer specialises in horary. She is the principal of the STA school of traditional horary astrology, which offers courses by correspondence and intensive residential seminars.
© Deborah Houlding.
This article was first published in The Traditional Astrologer Magazine, Issue 15, October 1997, pp.18-23.
Reproduced online 2003.