Person: Regiomontanus, Johann Müller
Regiomontanus or Johann Müller was a German scholar who made important contributions to trigonometry and astronomy.
Mathematical Profile (Excerpt):
- The Latin version of Königsberg (meaning King's mountain) is Regio Monte or, as it later became, Regiomontanus.
- What attracted Regiomontanus to Vienna was principally the 85-year old University and especially its activity in mathematical astronomy and cosmology.
- Courses Regiomontanus gave at Vienna included one on perspective in 1458, one on Euclid in 1460, and one on Virgil's Bucolics in 1461.
- When Peurbach was on his deathbed in 1461, he begged Regiomontanus to complete the Epitome of the Almagest and Regiomontanus enthusiastically carried on the work.
- The Defence of Theon against George of Trebizond was another work which Regiomontanus probably began think about around this time.
- Cardinal Bessarion now became Regiomontanus's patron and he travelled to Italy with his patron arriving in Rome on 20 November 1461.
- The astrolabe was presented by Johannes Regiomontanus, whose patron was Bessarion.
- Regiomontanus, the foremost European astronomer of the time, was commissioned by the Cardinal to prepare an Epitome of Ptolemy's "Almagest" Ⓣ(The major thesis: from the Arabic 'al-majisti' -- the Arabic translation of the Greek 'Mathematike Syntaxis' later translated into Latin as 'Magna Syntaxis'), also dedicated to him in 1462.
- The years 1461 to 1465 Regiomontanus spent as a member of Bessarion's extended household based mostly in Rome.
- As well as the time spent in Rome, he travelled in Italy with Bessarion spending the summer of 1462 at Viterbo, Cardinal Bessarion's favourite summer residence, and, when Bessarion left for Greece in the autumn of that year, Regiomontanus accompanied him as far as Venice.
- Bylica and Regiomontanus became friends at this time.
- On 19 June 1465 Regiomontanus made an observation at Viterbo, again in the summer residence.
- Certainly we know that by 1467 Regiomontanus was in Hungary having accepted an appointment from the King to the Royal Library in Buda.
- This provided an ideal position for Regiomontanus since it enabled him to both work with Martin Bylica on astronomy and also to enjoy his passion for old books.
- One of the old books which Regiomontanus had come across in 1462 while he was in Venice, was an incomplete copy of Diophantus's Arithmetica.
- Regiomontanus never translated Diophantus's Arithmetica and he never found a complete version.
- Indeed nobody has ever discovered a complete version, but this important discovery by Regiomontanus marks the beginning of the Arithmetica becoming known in Europe.
- Regiomontanus made important contributions to trigonometry and astronomy.
- We have mentioned the above the Epitome of the Almagest which was begun by Peurbach but completed by Regiomontanus.
- In the Epitome Regiomontanus, realising the need for a systematic account of trigonometry to support astronomy, promised to write such a treatise.
- Regiomontanus structured his work in a similar way to Euclid's Elements.
- When he was in Hungary, Regiomontanus computed two tables of sines.
- We know that Regiomontanus had indeed been making observations in Nuremberg for he observed a lunar eclipse there on 2 June 1471.
- Regiomontanus's interest in the motion of the Moon led him to make the important observation that the method of lunar distances could be used to determine longitude at sea.
- Regiomontanus describes how the position of the Moon can be used to determine longitude in the Ephemerides for the years 1474-1506 which he published.
- Regiomontanus realized the potential value of printing for producing identical multiple copies of scientific texts, which could be carefully edited with accurate diagrams.
- Pope Sixtus IV summoned Regiomontanus to Rome in 1475 to advise on calendar reform and he left Nuremberg some time after 28 July when he recorded his last observation there.
- Bernhard Walther, his wealthy pupil who had funded his instrument shop, observatory and printing works, began observations from Regiomontanus's observatory in Nuremberg on 2 August.
- It is certain that Regiomontanus had left Nuremberg by then.
- It seems a rather unlikely scenario, however, for others criticised George of Trebizond as vigorously as did Regiomontanus yet no attempts appear to have been made on their lives.
- Much more likely is that, after the Tiber overflowed its banks in January 1476 and there was a resulting outbreak of plague, Regiomontanus became its victim.
Born 6 June 1436, Unfinden (near Königsberg), Lower Franconia (now in Bayern, Germany). Died 6 July 1476, Rome (now Italy).
View full biography at MacTutor
Tags relevant for this person:
Analysis, Ancient Greek, Astronomy, Geometry, Origin Germany, Number Theory, Puzzles And Problems, Special Numbers And Numerals
Thank you to the contributors under CC BY-SA 4.0! 
- Github:
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- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
