Kepler, Johannes

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Kepler, Johannes Gender: M
born on 27 December 1571 Jul.Cal. (6 Jan 1572 greg.) at 14:37 (= 2:37 PM )
Place Weil der Stadt, Germany, 48n45, 8e52
Timezone LMT m8e52 (is local mean time)
Data source
Rodden Rating B
Collector: Rodden
Astrology data s_su.18.gif s_capcol.18.gif 15°28' s_mo.18.gif s_gemcol.18.gif 04°02 Asc.s_gemcol.18.gif 24°25'

Alternative birthtime
Kepler's own chart 13:00 LAT, 13:07 LMT
Date 27 December 1571 Jul.Cal. (6 Jan 1572 greg.) at 13:07 (= 1:07 PM )
Place Weil der Stadt, GER, 48n45, 8e52
Timezone LMT m8e52 (is local mean time)
Astrology data s_su.18.gif s_capcol.18.gif 15°24' s_mo.18.gif s_gemcol.18.gif 03°15 Asc.s_taucol.18.gif 28°23'

Johannes Kepler


German author, mathematician, scientist, astronomer, court astrologer and teacher. Known as "the father of modern astronomy," he discovered the three laws of planetary motion which paved the way a half century later for Newton's laws of universal gravitation. The leading astronomical theorist for over 400 years, he was regarded as having "one foot in medieval mysticism and one foot in the scientific method."

The son of peasants, Keplers' prodigious ability placed him as a student in the University of Tubingen, where he was strongly influenced by Copernican teachings. Following graduation, he was professor of mathematics at the University at Graz where he wrote "Mysterium Cosmographicum" in 1596, a treatise which initiated a correspondence with Danish Astronomer Tycho Brahe, who subsequently employed Kepler as his assistant at his observatory near Prague, 1600. It was there Kepler discovered his laws of planetary motion governing elliptical orbits, which were motivated by his desire to prove the Pythagorean Music of the Spheres.

Following Brahe's untimely death the following year, Kepler succeeded him as Court Mathematician to Holy Roman Emperor Rudolf II, King of Bohemia and Hungary. After publishing Brahe's calculations on the orbit of Mars in 1609, he became Mathematician to the States of Upper Austria and moved to Linz in 1612, where he wrote "De Cometis and Harmonic Mundi."

Kepler had doubts about astrology; nevertheless, he observed "A most unfailing experience (as far as can be expected in nature) of the excitement of sublunary (that is, human) natures by the conjunctions and aspects of the planets has instructed and compelled my unwilling belief." He repeatedly penned letters to friends to "separate the gems from the slag," and in later years, accepted the position of Court Astrologer to Albrecht Wallenstein, Bohemian general and imperial commander of armies in the Thirty Years War. Despite his rank as a Court Astrologer, Kepler lived on the edge of poverty and died in this condition on 11/15/1630 in Regensburg, Germany.

In the early 1800's, Catherine II of Russia purchased his manuscripts and placed in the observatory at Pulkovo near St. Petersburg, where they allegedly remained. While a member of academia was casually rummaging through an obscure archive at the University of California at Santa Cruz in March 1999, he found a letter "written in the hand of Kepler, from the collection of Kepler manuscripts in Pulkova" illustrating and delineating a horoscope, and was later verified to be authentic.

Link to Wikipedia biography

Link to Astrodienst discussion forum


  • associate relationship with Fabricius, David (born 9 March 1564 Jul.Cal. (19 Mar 1564 greg.)). Notes: Shared correspondence
  • business associate/partner relationship with Brahe, Tycho (born 14 December 1546 Jul.Cal. (24 Dec 1546 greg.))


  • Death, Cause unspecified 15 November 1630 (greg.) at 11:05 AM in Regensburg (Age 58)
    chart Placidus Equal_H.

Source Notes

Given by him in his book, "Harmonics, Book IV," (December 27, 1571 OS)

Nick Kollerstrom in The Mountain Astrologer April/May 2001, quotes Arthur Koestler, "The Watershed: A Biography of Johannes Kepler," 1960 and P.I.H. Naylor in "Astrology: A Fascinating History," which quotes Kepler discussing his own chart, "The 25th degree of Gemini was rising and the 22nd degree of Aquarius culminating."

Juan Revilla (Internet 8/2000) quotes a chart for 1:00 PM LAT, with an MC of 29 Cap 30 and ASC 28 Taurus, "drawn by Kepler himself on page 6 of "Johannes Kepler Selbstzeugnisse" by Franz Hammer et als, Stuttgart, 1971." Apparently Kepler had rectified his own chart from an aproximate time of 1:00 PM and by using a pre-natal epoch system, Trutina Hermetis or something similar, had arrived at 2:37 PM LMT.

He states that" Kepler later rectified this, which gave him 2:30, and from which he derived all that detailed data on his pre-natal epoch, obviously calculated in retrospective and from a general theory.

Juan Revilla adds the history (7/2000):

As you know, the time of birth usually given is 2:30 p.m., taken from Kepler himself. Arthur Koestler in "The Sleepwalkers" (e.g. p.227 Penguin Books, 1977) reproduces this data and gives details about the exact time in which he was conceived: 4:37 a.m., May 16, 1571. This is obviously an after-the-fact calculation made by Kepler himself, which further says that the pregnancy lasted 224 days, 9 hours, and 53 minutes. Koestler gives as reference (note #1, page 584) 'Opera Omnia' Vol.VII, p.670 seq.

But I have a photocopy of a facsimil reproduction of Kepler's horoscope drawn by his own hand, which appears in page 6 of "Johannes Kepler Selbstzeugnisse", by Franz Hammer et als, Stuttgart, 1971. I don't know any

German, and I didn't copy the rest of the book (this was many years ago, I hope I got the bib. reference OK). This is what it says below the reproduction (for those of you who read German):

<<Keplers Horoskop. Eigenhandig. Pulkovo, Kepler-NachlaB, Band 21, Blatt 450v.>>

This chart is drawn for 1 p.m. 27 Dec. 1571, which is clearly written in the inner square of the drawing, putting the Sun and Venus conjunction in the 9th house, and the Ascendant in late Taurus. Below this birth data, there is something added by Kepler's hand, where I can distinguish "2-1/2" and "Conceptionem" or something similar; I may be wrong in this last one. of course... it requires an expert to distinguish what is written there.

Since this horoscope has been drawn by Kepler himself, the following hypothesis seems very reasonable to me:

1- The original birth data available to Kepler to cast his horoscope was 1 p.m. (true solar time). This is the time that should be used.

2- Kepler later rectified this with the Trutina Hermetis or something similar, which gave him 2:30, and from which he derived all that detailed data on his pre-natal epoch, obviously calculated in retrospective and from a general theory. (This, presumably, could be put to test by someone familiar with this technique)

3- Kepler's birth time is not 2:30, but 1 p.m.

In my notes, I have the following references from the 'Gesammelte Werke' (Beck, Munchen) where Kepler discusses his own chart:

- "De Stella Nova" Chap.X (G.W.Vol.1 p.196)

- "Harmonice Mundi", IV, 7 (G.W.Vol.6 pp.278-9)

- "Astronomia Nova" (G.W.Vol.3 pp.261-2)

The chart is drawn by Kepler using Regiomontanus houses. Here are the positions, for those that want to compare:

Sun = 15.2 Cap

Moon = 4.10 Gem

Mercury = 7.35 Cap

Venus = 18.12 Cap

Mars = 8.57 Lib

Jup = 18.38 Pis

Sat = 4.12 Sco

Node = 2.37 Leo

10 = 29,30 Cap

11 = 20.12 Aqu

12 = 3.11 Ari

1 = 27.59 Tau

2 = 27.14 Gem

3 = 14.7 Can

Part of Fortune = 17.7 Libra


Srarkman rectified to 13.29.21 LMT Asc 5Gem45'


  • Traits : Mind : Exceptional mind (Upholder of Copernicus' theory)
  • Vocation : Science : Astronomy
  • Vocation : Science : Mathematics/ Statistics
  • Vocation : Writers : Astrology
  • Notable : Famous : Historic figure (Scientist, astrologer)
  • Notable : Famous : Top 5% of Profession
  • Notable : Book Collection : American Book