Technikatörténeti szemle 12. (1980-81)

TANULMÁNYOK - Ifj. Bartha Lajos: A legrégebbi magyarországi alapmeridiánok történetéhez

Verhandlungen, 1884. = Verhangdlungen des 4. Deutschen Geographentag zu München, 1884. Berlin, 1884. p: 46. Wargentin, 1781. — Wargentin, P. W.: Auszug einem französiche Schreiben

... Bode's Astronomisches Jahrbuch, 1781. Berlin, 1778. p: 272—278. Witauschek, 1934. = Witauschek Gy.: Történelmi jegyzetek a térképészet tárgyköréből I. köt. Ókor. A „Térképészeti Közlöny" 7. sz. különfüzete. Budapest, 1934. Witauschek, 1936. = Witauschek Gy.: Hosszúságkülönbségek meghatározása lőporjelek útján. — Térképészeti Közlöny, IV. köt. 1—2. sz. 1936. p: 82—90. Wodetzky, 1913. = Wodetczky J.: A kezdő meridiánok története. — Természettud. Közi. 45. évf. 1913. p: 215—216. Wolf, I—II. — Wolf, R.: Handbuch der Astronomie, ihre Geschichte und Literatur. Bd. I—II. Zürich, 1890, 1892. Zacft, 1799. = Zach, F. X.: Allgemeine Geographische Ephemeriden, Bd. IV. 3. Stück, Gotha, 1799. p. 272—278. (Schedius Lajos budai professzor levelei.) Zinner, 1936. = Zinner, E.: Régiómon tanús Magyarországon. — Mathematikai és Természettudományi Értesítő. 55. köt. 1936. p: 16. Zinneer, 1967. = Zinner, E.: Leben und Wirken Joh. Müller von Königsberg, genannt Regiomontanus. O. Zeller, „Milliaria" X. 1. Osnabrück, 1967. p: 26—46, 145. Zolnay, 1969. = Zolnay L.: Ünnepek és hétköznapok a középkori Budán. Budapest, 1969. p: 178—179. L. BARTHA, JR.: ON THE HISTORY OF THE OLDEST HUNGARIAN BASIC MERIDIANS From the early renaissance on cartographic work, time determinations and computing of almanachs made an accurate determination of the first meridian (zeromeridian), i.e. of the starting point for geographical longitude necessary and important. Development of national charts and of national time systems and calendars reaulted in a fixing of local basic meridians valid for smaller regions (lands, districts). The basic meridians are longitude circles lenked to the zero meridian by means of precise astronomical measurements. In Hungary during te XV

th

—XVI

th century the existence of a basic meridian is uncertain. The existence of Buda- and Esztergom-meridians can not be proved; the Nagyvárad-meridián has not been measured by G. Peuerbach („Tabulae Waradiensis, 1455") but it was only marked by estimation. The first Hungarian basic meridian was constructed by the professors of Nagyszombat University for cartographic and calendar purposes in 1658 (Joh. Misch, „Calendarium Tyrnaviense"). The Pozsony meridian was determined by Samuel Mikoviny in 1728 by means of Moon eclipses for cartographic purposes. The error of this determination was only +9'21". For astronomical time mesasurements F. Weiss and M. Hell measured a permanent meridian in Nagyszombat in 1760 with an error of ±14". Of great importance was the observation of the meridian crossing the astronomical observatory of Buda University in 1779—80 (Hell, Weiss, Bruna). This served as basis for the time service and cartographic work for the country till the beginning of XIX. century. In 1815 this was transposed to the Observatory built on the Gellért Hill (J. Pasquich, K. L. Littrow, D. Kmeth). This was located 1097,7 m south of the old spot. The recent triangulation base point was built on this spot, 17 m to the west from the original one. From 1867 till 1891 the national time meridian crossed the passage instrument of the Buda Real Secondary School (today: Toldy Gynasium). The table contains the Hungarian basic meridians, the year of their determination, their geographical longitudes (relative to Greenwich), the error of the determination and the zero-meridian serving for reference. The first three items are only „phantom meridians" without a proved existence.