Johannes Kepler - the man who opened the door to space.

The 15. May 1618 – the day the famous Astronomer Johannes Kepler (1571 – 1630), a German natural philosopher, mathematican, astronomer, astrologer, optican and evangelic theologian, wrote history.

After decades of hard work he discovered the truth behind the motion of planets. “De motibus planetarum“, as it's called in the original Latin written title of Book V in Harmonices Mundi published in 1619 in Linz Austria. Triumphing he declared his 3rd Law: “It's dead sure and is true, that the proportion existing between the period of revolution of some two planets is exactly one and a half of the proportion of their average distances“. In persistant dedective work, based on Tycho Brahes exactly observations he discovered the true distances. His investigative skills set him already in earlier times on the right track, there must be a correlation between orbit radius and circulation periods. Now after long search and try he was successful. Beeing so happy and conscious of his dedection's importance he wrote this memorable date in his famous book Harmonices Mundi. “15.Maji anni millesimi sexcentesimi decime octavi“ - 15. Mai 1618.

Kepler third law in Harmonices Mundi Libri V page 189

Where happened all this ? In Linz (Austria), where another dedective story, 400 years later, around this date happened. In Linz Kepler wrote most of his revolutionary works. They are milestones of astronomy and mathematics. It was always a mystery where he lived at this time in Linz. A friend of mine, Erich Meyer , an dedicated amateurastronomer of our local Astronomical association (Linzer Astronomische Gmeinschaft-"Johannes Kepler“), who was always fascinated from this great historic citizen of Linz, started a 2 year lasting dedective work to search out Keplers living house. Local renowned historians failed because of lacking astronomical knowledge but Meyer could lift this secret. Besides much historic investigation he did a lot of astronomical dedective work and calculations based on Keplers' original, and very exactly observing reports from different local astronomical events like solar and moon eclipses. He compared all detailed descriptions from Kepler about surrounding conditions during these events and examined how this description fits in with the circumstances of the relevant buildings. He calculated exactly the local path of the moon eclipse from August 1616 (and other eclipses too). Kepler's description of the visibility of his house for the moon eclipse of 26.8.1616 is only correct for one house in the Hofgasse. Also all other eclipse records fit exactly to this realization.!

The mystery of Johannes Kepler's residence from 1613 to 1620 in the Linzer Hofgasse can therefore be regarded as having been solved without any doubt after 400 years! It is Hofgasse 7 in Linz. A short abstract concerning Erich Meyer's work you can find HERE.

Additionaly I proudly present the todays APOD (Astronomy Picture Of the Day) showing Kepler's living house, where history was written.

Best regards


AWB signatur

J O H A N N E S   S T U E B L E R
Ambassador and National Coordinator AUSTRIA
of Astronomers Without Borders - AWB
TWAN-Austria event coordinator
National Organizer Sidewalk Astronomers
Member of LAG - Astronomical Society of Linz
Fellow of the Royal Astronomical Society
Associate of the IAU Division Commission C2
Charter member of A4E - Astronomy for Education
Consulter - Project "Keplarium"
About me:
Owner of Austrian Polarstern-Prize 2017
400-year-anniversary 3rd Kepler-Law



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