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Jakob BARSCHIUS, German astronomer & Kepler
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
"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
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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