Catholic Encyclopedia (1913)/Francis a Paula Triesnecker
Astronomer, b. at Kirchberg on the Wagram, in Lower Austria, 2 April, 1745; d. at Vienna 29 January, 1817. At the age of sixteen he entered the Society of Jesus, and, after several years' study of philosophy (Vienna) and mathematics (Tyrnau), he taught at various Jesuit colleges. After the suppression of the Society he went to Gras, where he completed his theological studies and was ordained shortly afterwards. He soon attained a reputation as a mathematician and astronomer and was appointed assistant to the director of the Vienna Observatory, Father Max Hell, whom he succeeded in 1792. He occupied this post during the remainder of his life. Triesnecker was thoroughly grounded in the science of mathematics and its applications to astronomy; and the accuracy of his observations, which in spite of ill-health he pursued till an advanced age, was universally recognized. His numerous treatises mainly deal with geography and astronomy. A considerable portion of his time was taken up by the "Ephemerides" of Vienna, the editorship of which, after Father Hell's death, he shared with the ingenious computer Burg. In this periodical he published, between the years 1787-1806, his "Tabulae Mercurii, Martis, Veneris, Solares", and the greater part of his micrometrical observations of the sun, moon, planets, and positions of stars. His "Novae motuum lunarium tabulae" were published separately in 1802. Other astronomical investigations may be found in "Zach's monatliche Correspondenz", in the "Commentarii soc. leg. Götting.", and in Bode's "Astron. Jahrbuch". In geography he determined or corrected the longitude and latitude of various places from the best available data. The results of this labour are embodied in the periodicals referred to above, the "Transactions of the Royal Soc. of Bohemia", and Zach's "Allgemeine geographische Ephemeriden". He completed Father Metzburg's triangulation of lower Austria, using it as a basis for the production of a new map of that country, and assisted him with the triangulation of Galicia. The erection of the "New Observatory" of Vienna (which afterwards gave place to the new structure on the "Turkenschanze") was Triesnecker's work. He was a member of the scientific associations of Breslau, Göttingen, Munich, St. Petersburg, and Prague.