Read more at —


Wikipedia on Tycho


Wikipedia on Kepler


Kepler’s Laws


The Tychonic System


Books —


Arthur Koestler  ‘The Sleepwalkers’  Arkana 1989


Kitty Ferguson  ‘Tycho and Kepler ...’  Walker & Co 2004 (also published as ‘The Nobleman and his Housedog’)


Flamsteed Astronomy Society

Huygens, Halley & Harrison

— Anniversaries 2006

1546, December 14th — 460 years ago, Tycho Brahe was born to wealthy nobility in Denmark.  Due to rather strange circumstances he was raised by his uncle, although this seems to have liberated him somewhat from ancestral expectations and allowed him more academic flexibility.  He got interested in astronomy while studying in Copenhagen and was inspired by the eclipse of 1560.  His foster parents wanted him to get experience abroad and sent him off to study in foreign universities in Leipzig, Wittenburg, and Rostock.  In Rostock he got into a duel with another Dane and had the bridge of his nose cut off.  He had a false nose piece made from an alloy of gold and silver to cover the disfigurement.  He returned to Denmark in 1570 when his father was dying.  By 1571 he had set-up an observatory and alchemical laboratory in Herravad Abbey. 

On November 11th 1572 Tycho emerged from a long session in the dark lab to be confronted by a bright star in Cassiopeia where he was sure there had not been a bright star before.   His measurements showed it was far beyond the Moon, in the sphere of the fixed stars which Aristotle and Ptolemy claimed to be unchanging.  Tycho’s Nova Stella (new star) showed they were wrong, brought him fame across Europe, and gave us the word ‘Nova’ (although we now know that what he saw was in fact a Supernova).

By 1575 Tycho had decided to leave Denmark for Basel, but the king of Denmark didn’t want to lose him.  The king persuaded him to stay by the gift of an island, Hven (pronounced Veen), off Copenhagen, and a lot of money to build and maintain an observatory there.  Tycho built a superb observatory-palace called ‘Uraniborg’ and equipped it with the best pre-telescopic instruments in Christian Europe. 

In 1577 Tycho again hit the headlines with his observations of a bright comet.  He was able to show that the comet was also beyond the Moon (in fact beyond Venus) again demonstrating that Aristotle was wrong.  According to Aristotle, comets were phenomena in the Earth’s atmosphere (but then, old Aristotle was a bu**er for the bottle)

Tycho’s observatory was extended in 1584 with the addition of an entire new complex called Stjerneborg.   He was running a large research establishment with a numerous full-time staff, and producing the most accurate and comprehensive sets of observations yet seen.  Tycho’s catalogues were accurate to between 30 and 60 seconds of arc and set the standard for 100 years.  In addition he formulated a new description of the solar system — the ‘Tychonic System’ was an attempt to reconcile Ptolemy and Copernicus :  in Tycho’s universe, the Earth was stationary at the centre, and the Moon and Sun orbited the Earth, but all the other planets orbited the Sun.  It too declined into the scrap-heap along with Ptolemy’s system, after Galileo hammered-in the final nails.

By 1597 Tycho had fallen out with the new king and flounced out of Hven taking his instruments with him.  Eventually he settled in Prague where he had been appointed Imperial Mathematician to Holy Roman Emperor Rudolph II.  In Prague he met up with Johannes Kepler, a talented mathematician from Graz.  Kepler had almost pursued Tycho across Europe in an effort to get access to Tycho’s 38 year series of observations, especially of the planet Mars.  His work with Tycho’s superb observations would lead to Kepler’s Laws, the first accurate descriptions of planetary motion.  Tycho’s measurements were the first with enough precision to allow Kepler’s analysis to find that the orbits are elliptical.

Tycho died on October 24th 1601.  He had sat too long at the dinner table without going to relieve himself, and died in great pain from the resulting bladder infection.  He was just 54.

Tycho was succeeded as Imperial Mathematician by Kepler who went on to compile the Rudolphine Tables of planetary motions, named for the Emperor.  Eight years after Tycho’s death, Galileo pointed his new telescope at the heavens ...

Tycho Brahe 1546-1601

And last, but by no means least Tycho Brahe

How to pronounce

‘Tycho Brahe’


Most people tend to say

‘Ty-co Bra-hay’


Apparently, in Danish, it should be said ‘Tee-co Braw’


so I understand ...

Tycho ‘the noble Danish Knight’ in the Painted Hall, Old Royal Naval College, Greenwich

Johannes Kepler  1571-1630

Tycho’s ‘Uraniborg’ Observatory and great quadrant

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