Petrus+Aplanus

=**Introduction**=

Petrus Aplanus who had many names such as Peter Apian, Peter Bennewitz, and Peter Bienewitz.Petrus Aplanus was born in 1501 in Leisnig, Saxony he went to Leipzig University when he was 15 years old and Latinized his original last name Bienewitz which means ("of the bees") into Apianus. He then went to the University of Vienna were he studied with Georg Tanstetter who was a mathematician, astronomer and an astrologer. In 1520 Petrus Aplanus he began to publish his first works and in 1523 left the University of Vienna. In 1524 Apianus he made his first book Cosomographicus liber were he used the cross-staff to measure lunar distances. He also found ways and invented instruments to find the time while it is night time, One of the items he made was called the "nocturnal" which is a fixed or a portable instrument used to tell time by the apparent revolution of the stars on the celestial sphere. Then in 1527 he was appointed as a professor at the university of Ingolstadt. In 1531 he was observing a comet when he noticed that it had a tail, and in 1532 he published Practica and said the a comets tail is always pointing away from the sun. Apianus then went to astronomical calculations and made the torquetum, which was a device that measured the ecliptic, equatorial, and altazimuth coordinates of a celestial body.

=**Contributions**=

Petrus Aplanus accomplished many things from when he was 15 till he died. Aplanus at a very young age went to the University of Vienna and graduated. Aplanus also published many books on astrology like the practica, Aplanus made a map of 48 Ptolemaic constellations which were discovered by Ptolemy, he also made some really good inventions which would help other famous astrologers later. The cross staff which Aplanus used to measure the lunar distance, he also made the lunar compass and the nocturnal which were used to find the time at night, also he made the torquetum which was a device that measured the ecliptic, equatorial, and altazimuth coordinates of a celestial body. By using the cross staff to measure the lunar distance he inspired Amerigo Vespucci and Johann Werner to use the cross staff to measure the longitude of a locality. Cosmographia was what got him into the University of Ingolstadt and if he did not do that he may not have wrote even more famous books. Astronomicum Caesareum possibly his most famous book that he dedicated to Charles V which showed how to use some inventions that helped calculate the planetary positions, but now today their are thought to be only 16 copies off the book left and very few of those are supposed to have nothing missing from when it was made. Aplanus isn’t widely known but he has some really good inventions that helped more famous astrologers do there work better than they would have if he had not of made and or perfected the inventions.

=**Later Years**=

In Petrus Aplanus' later years he published the "Cosmographicus liber" which Emperor Charles V was really interested in. Charles V found it so interesting that he publicly honored him in Regensburg in 1530. He then gave Petrus Aplanus the right to print in 1532 and a coat of arms in 1534. Therefore petrus aplanus dedicated his "Astronomicum Caesareum" to Charles V and his brother. The book was a tome with many artistically intricate discs that showed the movement of the planets. Charles V then made Petrus Aplanus head mathematician in 1541, honored him with knighthood and gave him the title of Imperial duke of the court and palatinate. Petrus Aplanus was one of the most important scholars and inventors of the renaissance. Petrus Aplanus died on April 12, 1552 in Ingolstadt, Bavaria.