Johann Gabriel Doppelmayr (September 27, 1677 – December 1, 1750) was a German mathematician, astronomer, cartographer, and wrote about sundials. (His surname is also spelled Doppelmayer and Doppelmair.)
He was born in Nuremberg, Germany, the son of the merchant Johann Siegmund Doppelmayr. He entered the Aegidien-Gymnasium in Nuremberg in 1689, then the University of Altdorf in 1696. His studies included mathematics, physics, and jurisprudence. Later he continued his studies in Halle[1] and graduated in 1698 with a dissertion on the Sun.
During studying at the University of Halle, he also learned French and Italian. After giving up his legal studies he then spent two years travelling and studying. In addition to his native Germany, he is known to have passed through the Netherlands and England, spending time at Utrecht, Leiden, Oxford, and London.
His career was academic, and he became professor of mathematics at the Aegidien-Gymnasium from 1704 until his death. He is not noted for any discoveries, but he did publish several works of a scientific nature. His publications covered topics on mathematics and astronomy, including sundials, spherical trigonometry, and celestial maps and globes. One of his works also included useful biographical information on several hundred mathematicians and instrument makers of Nuremberg. In 1742 he completed the Atlas Coelestis of the monk Johann Batiste Homann, a frequent collaborator.
He married Susanna Maria Kellner in 1716, and the couple had four children of which one survived. Doppelmayr became a member of several scientific societies, most notably the Berlin Academy, the Royal Society in 1733, and the St. Petersburg Academy of Sciences (1740).
The crater Doppelmayer on the Moon was named after him by Johann Hieronymus Schröter in 1791. The minor planet 12622 Doppelmayr is also named in his honour.