Franz de Paula Triesnecker (2 April 1745 – 29 January 1817) was an Austrian Jesuit astronomer. Biography Triesnecker was born in Mallon, Kirchberg am Wagram, Austria. When he was 16 he joined the Society of Jesus. He studied philosophy in Vienna and mathematics at Tyrnau, then became a teacher. Following the suppression of the Jesuits in 1773, he moved to Graz to complete his studies in theology, and was ordained soon after his graduation. In 1782 he became assistant director of the Vienna Observatory and 1792 succeeded Maximilian Hell as director. He remained in this post for the rest of his life. In 1794 he was elected Foreign Member of the Göttingen Academy of Sciences and Humanities. During his career he published a number of treatises on astronomy and geography. He was deputy editor of the Ephemerides Astronomicae of Vienna from 1782 until he became editor in 1792. He continued as editor, collaborating with Joanne Bürg, until he retired in 1806. He made a series of measurements of celestial bodies, which were published from 1787 until 1806. These included the Tabulae Mercurii, Martis, Veneris, Solares. He also carried out a long series of determinations of longitude that were noted for their accuracy. The crater Triesnecker on the Moon is named after him. Works 1787: Dissertatio Lalandi de novo Planeta latine reddita 1788: Tabulae Mercurii juxta Mayeri Göttingensis Elementa. Appendix 3 of Ephemerides Astronomicae Vindobonensem 1788 pp 418-455 1789: Tabulae Martis novae ex propriis Elementis constructae. Appendix 2 of Ephemerides Astronomicae Vindobonensem 1789 pp 289-331 1790: Novae Veneris Tabulae ex propriis Elementis constructae. Appendix 2 of Ephemerides Astronomicae Vindobonensem 1790 pp 325-352 1791: Methodus figuram telluris ex Eclipsibus Solis deducendi 1792: De proprio Motu Stellarum fixarum in Rectascensionem et Declinationem 1793: Tabulae solares novae ex observationibus deductae et ad Meridianum Parisiensem constructae. Appendix 3 of Ephemerides Astronomicae Vindobonensem 1793 pp 401-455 1793: Commentarium De Diminutione Obliquitatis eclipticae saeculari Commentarius. Appendix 4 of Ephemerides Astronomicae Vindobonensem 1793 pp 457-489 1794: Commentarium de De Massa Veneris. Appendix 3 of Ephemerides Astronomicae Vindobonensem 1794 pp 419-435 1795: De usu Aberrationis luminis in tectione Stellarum fixarum per Lunam 1796: Diameter apparens solis, lunae et planetarum cum micrometro objectivo observatus 1797: Differentiae Satellitum Jovis ope micrometri objectivi Dolandini observatae 1798: Catalogus fixarum Caillianus novis observationibus restauratus. Appendix 2 of Ephemerides Astronomicae Vindobonensem 1798 pp 298-310 1799: Longitudines Geographicae variorum locorum e Solis Eclipsibus et fixarum deductae.