Johannes Stadius, German astronomer, astrologer, mathematician (d. 1579)
Johannes Stadius or Estadius (Dutch: Jan Van Ostaeyen; French: Jean Stade) (ca. 1 May 1527 – 17 June 1579), was a Flemish astronomer, astrologer, and mathematician. He was one of the important late 16th-century makers of ephemerides, which gave the positions of astronomical objects in the sky at a given time or times.