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Re: Jakob BARSCHIUS, German astronomer & Kepler

This is a very nice commentary. I find the references to Galileo and Florence
quite interesting.

Dana Scott

Claudio Antonini wrote:

> Note below the mentions to Prague, Rudolph II, Kepler, Jakob Barscht (who
> become Kepler's son in law the same year that Kepler died), and other
> interesting events of the times. A few dates, the 1615-16 witch hunt and a
> work from Kepler concerning 'uterus' might also be of interest.
> I don't remember where it comes from, but Barschius was alternatively
> spelled as Baresch, which is not far from 'Bartsch'.
> The following is from
> http://es.rice.edu/ES/humsoc/Galileo/People/kepler.html, found using
> Altavista.
> "Except for Mercury, Kepler's construction produced remarkably accurate
> results. Because of his talent as a mathematician, displayed in this volume,
> Kepler was invited by Tycho Brahe to Prague to become his assistant and
> calculate new orbits for the planets from Tycho's observations. Kepler moved
> to Prague in 1600.
> Kepler served as Tycho Brahe's assistant until the latter's death in 1601
> and was then appointed Tycho's successor as Imperial Mathematician, the most
> prestigious appointment in mathematics in Europe. He occupied this post
> until, in 1612, Emperor Rudolph II was deposed. In Prague Kepler published a
> number of important books. In 1604 Astronomia pars Optica ("The Optical Part
> of Astronomy") appeared, in which he treated atmospheric refraction * but
> also treated lenses and gave the modern explanation of the workings of the
> eye; in 1606 he published De Stella Nova ("Concerning the New Star") on the
> new star that had appeared in 1604; and in 1609 his Astronomia Nova ("New
> Astronomy") appeared, which contained his first two laws (planets move in
> elliptical orbits with the sun as one of the foci, and a planet sweeps out
> equal areas in equal times). Whereas other astronomers still followed the
> ancient precept that the study of the planets is a problem only in
> kinematics, Kepler took an openly dynamic approach, introducing physics into
> the heavens.
> In 1610 Kepler heard and read about Galileo's discoveries with the spyglass.
> He quickly composed a long letter of support which he published as
> Dissertatio cum Nuncio Sidereo ("Conversation with the Sidereal Messenger"),
> and when, later that year, he obtained the use of a suitable telescope, he
> published his observations of Jupiter's satellites under the title Narratio
> de Observatis Quatuor Jovis Satellitibus ("Narration about Four Satellites
> of Jupiter observed"). These tracts were an enormous support to Galileo,
> whose discoveries were doubted or denied by many. Both of Kepler's tracts
> were quickly reprinted in Florence. Kepler went on to provide the beginning
> of a theory of the telescope in his Dioptrice, published in 1611.
> During this period the Keplers had three children (two had been born in Graz
> but died within months), Susanna (1602), who married Kepler's assistant
> Jakob Bartsch in 1630, Friedrich (1604-1611), and Ludwig (1607-1663).
> Kepler's wife, Barbara, died in 1612. In that year Kepler accepted the
> position of district mathematician in the city of Linz, a position he
> occupied until 1626. In Linz Kepler married Susanna Reuttinger. The couple
> had six children, of whom three died very early.
> In Linz Kepler published first a work on chronology and the year of Jesus's
> birth, In German in 1613 and more amply in Latin in 1614: De Vero Anno quo
> Aeternus Dei Filius Humanam Naturam in Utero Benedictae Virginis Mariae
> Assumpsit (Concerning the True Year in which the Son of God assumed a Human
> Nature in the Uterus of the Blessed Virgin Mary"). In this work Kepler
> demonstrated that the Christian calendar was in error by five years, and
> that Jesus had been born in 4 BC, a conclusion that is now universally
> accepted. Between 1617 and 1621 Kepler published Epitome Astronomiae
> Copernicanae ("Epitome of Copernican Astronomy"), which became the most
> influential introduction to heliocentric astronomy; in 1619 he published
> Harmonice Mundi ("Harmony of the World"), in which he derived the
> heliocentric distances of the planets and their periods from considerations
> of musical harmony. In this work we find his third law, relating the periods
> of the planets to their mean orbital radii.
> In 1615-16 there was a witch hunt in Kepler's native region, and his own
> mother was accused of being a witch. It was not until late in 1620 that the
> proceedings against her ended with her being set free. At her trial, her
> defense was conducted by her son Johannes.
> 1618 marked the beginning of the Thirty Years War, a war that devastated the
> German and Austrian region. Kepler's position in Linz now became
> progressively worse, as Counter Reformation * Counter Reformation measures
> put pressure on Protestants in the Upper Austria province of which Linz was
> the capital. Because he was a court official, Kepler was exempted from a
> decree that banished all Protestants from the province, but he nevertheless
> suffered persecution. During this time Kepler was having his Tabulae
> Rudolphinae ("Rudolphine Tables") printed, the new tables, based on Tycho
> Brahe's accurate observations, calculated according to Kepler's elliptical
> astronomy. When a peasant rebellion broke out and Linz was besieged, a fire
> destroyed the printer's house and shop, and with it much of the printed
> edition. Soldiers were garrisoned in Kepler's house. He and his family left
> Linz in 1626. The Tabulae Rudolphinae were published in Ulm in 1627.
> Kepler now had no position and no salary. He tried to obtain appointments
> from various courts and returned to Prague in an effort to pry salary that
> was owed him from his years as Imperial Mathematician from the imperial
> treasury. He died in Regensburg in 1630. Besides the works mentioned here,
> Kepler published numerous smaller works on a variety of subjects."
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fn:Dana Scott