Editing Tycho Brahe (section)

===Exile and later years===
{{Quote box |width=300px |align=right|quoted=true |
|salign=right
|quote=<poem>Denmark what is my offense? How
have I offended  my fatherland?
You may think that what I have done is wrong
But was I wrong to spread your fame abroad?
Tell me, who has done such things before?
And sung your honor to the very stars?</poem>
|source=Excerpt of Tycho Brahe's ''Elegy to Dania''{{sfn|Christianson|2000|page=216}}
}}
When Frederick died in 1588, his son and heir [[Christian IV of Denmark|Christian IV]] was only 11 years old. A regency council was appointed to rule for the young prince-elect until his coronation in 1596. The head of the council (Steward of the Realm) was [[Christoffer Valkendorff]], who disliked Tycho after a conflict between them, and hence Tycho's influence at the Danish court steadily declined. Feeling that his legacy on Hven was in peril, he approached the Dowager Queen Sophie and asked her to affirm in writing her late husband's promise to endow Hven to Tycho's heirs.{{sfn|Christianson|2000|p=141}} 

He realized that the young king was more interested in war than in science, and was of no mind to keep his father's promise. King Christian IV followed a policy of curbing the power of the nobility, by confiscating their estates to minimize their income bases, by accusing nobles of misusing their offices and of heresies against the Lutheran church. Tycho, who was known to sympathize with the [[Philippists]], followers of [[Philip Melanchthon]], was among the nobles who fell out of grace with the new king. The king's unfavorable disposition towards Tycho was likely also a result of efforts by several of his enemies at court to turn the king against him.{{sfn|Björklund|1992}}

In addition to Valkendorff, Tycho's enemies included the king's doctor Peter Severinus, who also had personal gripes with Tycho. Several [[gnesio-Lutheran]] Bishops suspected Tycho of heresy{{snd}}a suspicion motivated by his known Philippist sympathies, his pursuits in medicine and alchemy, both of which he practiced without the church's approval, and his prohibiting the local priest on Hven to include the exorcism in the baptismal ritual. Among the accusations raised against Tycho were his failure to adequately maintain the royal chapel at Roskilde, and his harshness and exploitation of the Hven peasantry.{{sfn|Björklund|1992}}

[[File:Titelblad till bok om astronomi av Tycho Brahe, 1648 - Skoklosters slott - 99889.tif|thumb|The title page of {{lang|la|Astronomiae Instauratae, 1648 edition.}}]]
Tycho became even more inclined to leave when a mob of commoners, possibly incited by his enemies at court, rioted in front of his house in Copenhagen. Tycho left Hven in 1597, bringing some of his instruments with him to Copenhagen, and entrusting others to a caretaker on the island. Shortly before leaving, he completed his star catalogue giving the positions of 1,000 stars.{{sfn|Björklund|1992}} After some unsuccessful attempts at influencing the king to let him return, including showcasing his instruments on the wall of the city, he acquiesced to exile. He wrote his most famous poem, ''Elegy to Dania'' in which he chided Denmark for not appreciating his genius.{{sfn|Björklund|1992|p=33}}<ref name="Bra">{{cite web |last1=Brashear |first1=Ronald |title=Tycho Brahe: Astronomiæ instauratæ (1602) |url=http://www.sil.si.edu/DigitalCollections/HST/Brahe/brahe-introduction.htm#book |website=Smithsonian Libraries |publisher=[[Smithsonian Institution]] |access-date=19 July 2016 |date=1999}}</ref>

The instruments he had used in Uraniborg and Stjerneborg were depicted and described in detail in his [[star catalogue]] {{lang|la|Astronomiae instauratae mechanica}} or ''Instruments for the restoration of astronomy'', first published in 1598. The King sent two envoys to Hven to describe the instruments left behind by Tycho. Unversed in astronomy, the envoys reported to the king that the large mechanical contraptions such as his large quadrant and sextant were "useless and even harmful".{{sfn|Björklund|1992|p=33}}<ref name="Bra">{{cite web |last1=Brashear |first1=Ronald |title=Tycho Brahe: Astronomiæ instauratæ (1602) |url=http://www.sil.si.edu/DigitalCollections/HST/Brahe/brahe-introduction.htm#book |website=Smithsonian Libraries |publisher=[[Smithsonian Institution]] |access-date=19 July 2016 |date=1999}}</ref>

From 1597 to 1598, he spent a year at the castle of his friend [[Heinrich Rantzau]] at Haus Wandesburg in [[Wandsbek]] outside [[Hamburg]]. Then they moved for a while to [[Wittenberg]], where they stayed in the former home of Philip Melanchthon.{{sfn|Håkansson|2006|p=68}}

In 1599, he obtained the patronage of [[Rudolf II, Holy Roman Emperor]] and moved to Prague, as Imperial Court Astronomer. Tycho built a new observatory in a castle in [[Benátky nad Jizerou]], 50&nbsp;km from Prague, and worked there for one year. The emperor then brought him back to Prague, where he stayed until his death. At the imperial court even Tycho's wife and children were treated like nobility, which they had never been at the Danish court.{{sfn|Håkansson|2006|p=68}}

Tycho received financial support from several nobles in addition to the emperor, including Oldrich Desiderius Pruskowsky von Pruskow, to whom he dedicated his famous {{lang|la|Mechanica}}. In return for their support, Tycho's duties included preparing [[astrological chart]]s and predictions for his patrons at events such as births, [[weather forecasting]], and astrological interpretations of significant astronomical events, such as the supernova of 1572, sometimes called Tycho's supernova, and the Great Comet of 1577.<ref>Adam Mosley and the Department of History and Philosophy of Science of the [[University of Cambridge]]. [http://www.hps.cam.ac.uk/starry/tychoastrol.html "Tycho Brahe and Astrology"]. {{Webarchive|url=https://web.archive.org/web/20111208234739/http://www.hps.cam.ac.uk/starry/tychoastrol.html |date=8 December 2011 }}. 1999. Retrieved 2 October 2008</ref>

====Relationship with Kepler====
{{Main|Johannes Kepler}}

In Prague, Tycho worked closely with Kepler, his assistant. Kepler was a convinced Copernican, and considered Tycho's model to be mistaken, and derived from simple "inversion" of the Sun's and Earth's positions in the Copernican model.{{sfn|Jardine|2006|p=258}} Together, the two worked on a new star catalogue based on his own accurate positions{{snd}}this catalogue became the ''[[Rudolphine Tables]]''.{{sfn|Taton|Wilson|1989}} Also at the court in Prague was the mathematician Nicolaus Reimers (Ursus), with whom Tycho had previously corresponded, and who, like Tycho, had developed a geo-heliocentric planetary model, which Tycho considered to have been plagiarized from his own.{{sfn|Jardine|2006}}{{sfn|Mosley|2007|p=28}}{{sfn|Ferguson|2002}}

Kepler had previously spoken highly of Ursus, but now found himself in the problematic position of being employed by Tycho and having to defend his employer against Ursus' accusations, even though he disagreed with both of their planetary models. In 1600, he finished the tract {{lang|la|Apologia pro Tychone contra Ursum}} (defense of Tycho against Ursus).{{sfn|Jardine|2006}}{{sfn|Mosley|2007|p=28}}{{sfn|Ferguson|2002}} Kepler had great respect for Tycho's methods and the accuracy of his observations and considered him to be the new [[Hipparchus]], who would provide the foundation for a restoration of the science of astronomy.{{sfn|Christianson|2000|p=304}}