Everything remains to be done in his field and his achievements are frequent and numerous. In 1597 Galileo turns the compass into an instrument for the quantitative analysis of many geometric figures, for the purpose of military applications. He self publishes this promising invention in 1606. He replies in the following year by another book to Baldassare Capra who had accused him of plagiarism.
A copy of these scarce little books bound as a single volume is estimated £ 250K for sale by Christie's in London on July 13, lot 40.
Galileo had previously understood that meticulous observations of the sky can improve the modeling of physical phenomena. In 1604 his observation of a nova provides a first exception to Aristotle's doctrine of the immutability of the heavens, considered as an untouchable truth by the Church.
The greatest scientific advance made by Galileo comes in 1609 when a friend informs him of the realization of a longue-vue (spyglass) by Lippershey. Galileo desires to watch the sky with the method of this Dutch opticist. After a frenetic phase of trial and error, Galileo gets a satisfactory instrument.
The sky seen by Galileo with his telescope is very different from its traditional modeling. Within weeks the scientist discovers the complex texture of the Milky Way, the roughness of the surface of the Moon and the satellites of Jupiter. With this new information, astrology is suddenly losing its meaning.
He must act quickly to avoid falling again in anticipation quarrels. Galileo publishes his book Sidereus Nuncius (Sidereal Messenger) in Venice in March 1610. This is too much for the traditionalists. Galileo had been careful to hide the heliocentric hypothesis but his book definitively refutes the Ptolemaic system. Religious persecution will now begin but Galileo knows that his observations and their consequences are scientifically irrefutable.
A first issue of the Sidereus Nuncius is estimated £ 200K by Christie's in the same sale as above, lot 41.
RESULTS INCLUDING PREMIUM :
Compass (lot 40) : £ 240K
Astronomy (lot 41) : £ 315K