The
Rudolphine Tables consist of a
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
catalogue and planetary tables published by
Johannes KeplerJohannes Kepler was a German mathematician, astronomer and astrologer, and key figure in the 17th century scientific revolution. He is best known for his eponymous laws of planetary motion, codified by later astronomers based on his works Astronomia nova, Harmonices Mundi, and Epitome of...
in 1627 using data from Tycho Brahe's observations.
Star tables had been produced for many centuries and were used to establish the position of the planets relative to the fixed stars (particularly the twelve constellations used in
astrologyAstrology is a group of systems, traditions, and beliefs which hold that the relative positions of celestial bodies and related details can provide information about personality, human affairs, and other terrestrial matters. A practitioner of astrology is called an astrologer...
) on a specific date in order to construct
horoscopeIn astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, planets, the astrological aspects, and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from Greek words meaning "a look at the hours" In...
s. Until the end of the 16th century, the most widely used had been the Alphonsine tables, first produced in the 13th century and regularly updated thereafter.
The
Rudolphine Tables consist of a
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
catalogue and planetary tables published by
Johannes KeplerJohannes Kepler was a German mathematician, astronomer and astrologer, and key figure in the 17th century scientific revolution. He is best known for his eponymous laws of planetary motion, codified by later astronomers based on his works Astronomia nova, Harmonices Mundi, and Epitome of...
in 1627 using data from Tycho Brahe's observations.
Previous tables
Star tables had been produced for many centuries and were used to establish the position of the planets relative to the fixed stars (particularly the twelve constellations used in
astrologyAstrology is a group of systems, traditions, and beliefs which hold that the relative positions of celestial bodies and related details can provide information about personality, human affairs, and other terrestrial matters. A practitioner of astrology is called an astrologer...
) on a specific date in order to construct
horoscopeIn astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, planets, the astrological aspects, and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from Greek words meaning "a look at the hours" In...
s. Until the end of the 16th century, the most widely used had been the Alphonsine tables, first produced in the 13th century and regularly updated thereafter. These were based on a
PtolemeicClaudius Ptolemaeus , known in English as Ptolemy , was a Roman citizen of Greek ancestry. He was a mathematician, astronomer, geographer, astrologer and a poet of a single epigram in the Greek Anthology. He lived in Egypt under the Roman Empire, and is believed to have been born in the town of...
, geocentric model of the solar system. Although the Alphonsine tables were not very accurate, nothing else was available and so they continued to be used.
In 1551, following the publication of
De revolutionibus orbium coelestiumNicolai Copernici Torinensis De revolutionibus orbium coelestium, Libri VI , first printed in 1543 in Nuremberg, is the seminal work on heliocentric theory and the masterpiece of astronomer Nicolaus Copernicus...
by Nicholas Copernicus,
Erasmus ReinholdErasmus Reinhold was a German astronomer and mathematician, considered to be the most influential astronomical pedagogue of his generation. He was born and died in Saalfeld, Thuringia, Germany....
produced the Prussian Tables based on a heliocentric model of the solar system, but these were no more accurate than the earlier tables.
Brahe's data and Kepler's model of the solar system
Tychoe Brahe had spent much of his life obtaining measurements of the position of stars and planets to a much greater accuracy than had been possible previously. He wished these observations to be the basis of a new and more accurate set of star tables. Kepler was able to prepare these new tables using Brahe's accurate observations together with a heliocentric model of the solar system and his own discovery of the elliptical orbits of the planets. Accurate calculation was aided by the newly published system of
logarithmIn mathematics, the logarithm of a number to a given base is the power or exponent to which the base must be raised in order to produce the number....
s which simplified accurate calculation and made them less prone to errors.
Publication
While publishing the Rudolphine Tables, Kepler was hard-pressed to fight off Tycho's numerous relatives. During the publication process these relatives repeatedly tried to obtain control of the observations and the profit from the publication of the tables. They argued that Tycho's work should benefit his own family, and not one of Tycho's competitors. Kepler counter argued that he and Tycho had been collaborating on the data for many years before Tycho's death. Kepler further asserted that he was responsible for most of the calculations and also for the organization of the data. In the end Kepler did win control of the tables and published them himself while the Brahe family got no benefit from them.
Brahe had intended that the tables should be dedication to
Emperor Rudolf IIRudolf II , Holy Roman Emperor as Rudolf II , King of Hungary as Rudolf , King of Bohemia as Rudolf II and Archduke of Austria as Rudolf V...
, but by 1627 when the tables were published, he had died, so instead they were dedicated to Emperor Ferdinand II but are named after Rudolph. They contain positions for the 1,006 stars measured by
Tycho BraheTycho Brahe, born Tyge Ottesen Brahe , was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
, and 400 and more stars from
PtolemyClaudius Ptolemaeus , known in English as Ptolemy , was a Roman citizen of Greek ancestry. He was a mathematician, astronomer, geographer, astrologer and a poet of a single epigram in the Greek Anthology. He lived in Egypt under the Roman Empire, and is believed to have been born in the town of...
and
Johann BayerJohann Bayer was a German lawyer and uranographer . He was born in Rain, Bavaria in 1572. He began his study of philosophy in Ingolstadt in 1592, and moved later to Augsburg to begin work as a lawyer. He grew interested in astronomy during his time in Augsburg...
, with directions and tables for locating the
planetA planet , is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s of the
solar systemThe Solar System consists of the Sun and those celestial objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago...
. The tables included many function tables of
logarithmIn mathematics, the logarithm of a number to a given base is the power or exponent to which the base must be raised in order to produce the number....
s and antilogarithms, and instructive examples for computing planetary positions.
For most stars these tables were accurate to within one
arc minuteA minute of arc or arcminute is a unit of angular measurement, equal to one sixtieth of one degree. Since one degree is defined as one three hundred sixtieth of a circle, 1 minute of arc is 1/21,600 of the amount of arc in a closed circle...
, and were the first to include corrective factors for atmospheric
refractionRefraction is the change in direction of a wave due to a change in its velocity. This is most commonly observed when a wave passes from one medium to another...
. The tables were sufficiently accurate to predicted a
transit of MercuryA transit of Mercury across the Sun takes place when the planet Mercury comes between the Sun and the Earth, and Mercury is seen as a small black dot moving across the face of the Sun....
observed by
Pierre GassendiPierre Gassendi was a French philosopher, priest, scientist, astronomer, and mathematician. With a church position in south-east France, he also spent much time in Paris, where he was a leader of a group of free-thinking intellectuals. He was also an active observational scientist, publishing the...
in 1631 and a
transit of VenusA transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, obscuring a small portion of the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun. The duration of such transits is...
observed by Jeremiah Horrox in 1639.
External links
- Universitätsbibliothek Kiel – Digiport: Tabulæ Rudolphinæ - Bartsch
Jakob Bartsch or Jacobus Bartschius was a German astronomer.-Biography:Bartsch was born in Lauban in Lusatia. He was taught how to use the astrolabe by Sarcephalus , a librarian in Breslau...
version from 1627, with appendices on Schiller's Christian constellations and Bartsch'es own constellation innovations.