Johannes Stadius orEstadius (Dutch:Jan Van Ostaeyen;French:Jean Stade) (ca. 1 May 1527 – 17 June 1579), was aFlemishastronomer,astrologer, andmathematician. He was one of the important late 16th-century makers ofephemerides, which gave the positions of astronomical objects in the sky at a given time or times.
BornJan Van Ostaeyen in the town ofLoenhout (Loennouthesius, meaning 'from Loenhout', is sometimes appended to his Latin surname) in theDuchy of Brabant, Stadius grew up in theSchaliënhuis on the old Dorpsstraat, which was one of the oldest houses in Loenhout (today a tavern and restaurant). Not much else is known regarding his youth besides the fact that his parents were not married to each other.[citation needed]
After receiving his education at theLatin school ofBrecht, Stadius studiedmathematics,geography, andhistory at theOld University of Leuven, where one of his teachers wasGemma Frisius. After completing his studies, he became a professor of mathematics at his alma mater. In 1554 he left his home country and travelled toTurin, where he enjoyed the patronage of the powerful Duke ofSavoy.
Stadius subsequently worked inCologne,Brussels andParis. In Paris, he debated with thetrigonometristMaurice Bressieu ofGrenoble and madeastrological predictions for the French court. In hisTabulae Bergenses (1560), Stadius calls himself both royal mathematician (ofPhilip II of Spain) and mathematician to the Duke of Savoy.[1]
During his stay in Brussels Stadius published his first work, theEphemerides novae et auctae, first published by the publisher Arnold Birckmann ofCologne in 1554. Anephemeris (plural:ephemerides) (from theGreek wordephemeros, "daily") was, traditionally, a table providing the positions (given in aCartesian coordinate system, or inright ascension anddeclination or, for astrologers, inlongitude along thezodiacalecliptic), of theSun, theMoon, and theplanets in thesky at a given moment intime; the astrological positions are usually given for eithernoon ormidnight depending on the particular ephemeris that is used.
This work posited a link between mathematics and medicine and was influential onTycho Brahe andNostradamus. Stadius had been encouraged to publish theEphemerides by his old teacherGemma Frisius. Frisius had in a letter written in 1555 urged Stadius not to be afraid of being accused of believing in a moving earth and a stationary sun (i.e. the theory ofCopernicus) or of abandoning the medievalAlfonsine Tables in favor of his own observations. In this letter Frisius further wrote that the system devised byCopernicus gave a better understanding of planetary distances, as well as of certain features of retrograde motion. Frisius' letter was published in several editions of theEphemerides. The 1556 edition (Cologne)Ephemerides novae et exactae Ioannis Stadii Leonnovthesii ab anno 1554. ad annum 1570. ... can be consulted onlinevia KU Leuven Special Collections.
Stadius died in Paris where he is buried. The inscription on his epitaph states that he died on 17 June 1579 and that he had lived for nearly 52 years and 2 months. Stadius' estimated birth date of 1 May 1527 is based on this inscription.[1]
Thelunar craterStadius is named after Stadius.
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