TYCHO BRAHE'S STAR CATALOG / by Caitlin Murray

[Brahe was Rudolf II's court astronomer]

By 1592, Tycho had produced a catalogue of 777 stars, the first new catalogue known to the Latin West since the time of Ptolemy. This catalogue was printed for inclusion in the Astronomiae instauratae progymnasmata, although the book was not completed and issued until 1602, after Tycho's death. The work also contained his solar theory, including tables, completed by 1589, and a section on the lunar motions which took Tycho the rest of his life to complete. In the meantime, further observations on the fixed stars were made, to bring the number in the Tychonic catalogue to 1000; although many of the additional stellar positions were less accurate than the earlier ones. Tycho sent manuscript copies of this star catalogue to potential patrons in 1598 and 1599, along with the printed Astronomiae instauratae mechanica. Emperor Rudolph II also received a manuscript ephemeris of daily positions of the sun and moon for the year 1599.

Astronomical tables for all the planets were eventually printed on the basis of Tychonic data, as was the 1000-star catalogue, but not until 1627. The Tabulae Rudolphinae were completed by Johannes Kepler, and in accordance with his planetary theory. Although it was not immediately recognised, the positions predicted in this work were generally around thirty times better than those of previous and competing tables.

[Uranienborg] [was a Danish astronomical observatory operated by Tycho Brahe. It was built c. 1576 – c. 1580 on Hven, an island in the Øresund between Zealand and Scania, which at that time was part of Denmark. Shortly after its construction, the observatory was expanded with an underground facility, Stjerneborg, on an adjacent site] [The building was dedicated to Urania, the Muse of Astronomy, and it was named Uranienborg, "The Castle of Urania." ]

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QUID SI SIC? / WHAT IF?

(https://archive.org/stream/tychobrahepictur00dreyrich#page/106/mode/2up) pp. 107

1576 to 1597

His last words, "Ne frusta vixisse vidar" (May I not seemed to have lived in vain") were recorded by his assistant Kepler. Within a few years of his death, the castle and observatory he built on his beloved island Hven were destroyed.