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1. Introduction

The recent establishment of the IAU Meteor Data Center in Lund (Sweden) (Lindblad & Steel 1994), and an ongoing list of publications that make use of it, testify to the continued interest in meteor orbits. The advances in computer modeling has generated a new interest in meteor streams and their relationship to the parent comets (e.g. Fox et al. 1983; Jones 1985; Gustafson 1989; Williams & Wu 1993; Wu & Williams 1995). Key observations have been made in other fields, such as the discovery of IRAS dust trails in the orbit of short period comets (Sykes et al. 1986; Sykes & Walker 1992). Hence, new observations of meteor streams promise exciting discoveries and an increased understanding of meteor stream formation and evolution (Steel 1993; Jenniskens 1994).

Multi-station photography provides the very accurate orbital elements of meteoroids needed in theoretical studies. The accuracy of photographic orbits is typically an order of magnitude better than those of radar orbits. Unlike radar orbits, photographic data potentially allow resolving the intrinsic scatter in the distribution of orbital elements. The photographed meteors are typically in the size range of millimeter or centimeter size and larger, depending on entry velocity. These large grains contain most of the mass in comet ejecta and are least affected by radiation pressure.

The first meteor was photographed during the Andromedid storm of 1885 (Weinek 1886). An attempt at multi-station photography did not succeed at that time. Optical surveys of meteor orbits were started at Harvard where a small camera network was operated from 1936 to 1959 in a project led by F.L. Whipple (Whipple 1938). In total, some 1245 orbits were obtained (Lindblad & Steel 1994). Later, specially designed Baker Super-Schmidt cameras were used (Whipple 1947; Jacchia & Whipple 1956), from which almost 2529 orbits were measured (McCrosky & Posen 1961). Only 413 of these were calculated from a precise reductions of the data (Jacchia & Whipple 1961; Jacchia et al. 1967). At the same time, small camera surveys were performed in the former Soviet Union, in Dushanbe, Odessa and Kiev in the period 1940-1983, which resulted in 1111 precise orbits (e.g. Babadzanov & Kramer 1967). Small camera surveys have since been abandoned and are only used by amateur observers, with notable results by the Nippon Meteor Society (NMS) in Japan in the period 1974-1982 (325 orbits) (e.g. Koseki et al. 1990). These data, too, have not always been reduced precisely.

The Photographic Meteor Survey program of the Dutch Meteor Society started in 1982, when software developed at the University of Poznan (TURNER - Tadeusz 1983) and Ondřejov Observatory (REDCON, FIRBAL - Ceplecha et al. 1979) became available for astrometry and trajectory calculations. The programs were adapted for use on MS-DOS computers. Since that time, some of the older data in Betlem & de Kort (1976) have been reduced with the new techniques and the database now also contains some orbits from meteors dating back to 1972 (Betlem 1990). Preliminary results of 70 orbits were published in Betlem & de Lignie (1990).

In this publication we present all 359 meteor orbits of annual meteor streams and sporadic meteors obtained in the survey prior to August of 1993. Special attention is given to measurement uncertainty, which will allow addressing the intrinsic dispersion in meteor streams. An example will be given. In addition, the new data span a large gap in time between previous surveys in the mid 1950's and the present, which allows the first measurement of the rate of change of the orbital elements of the Geminid stream.


Name Location Nl/Fr N
C.R. ter Kuile Buurse/Lardiers 208
H. Betlem Varsseveld 183
M. de Lignie Oostkapelle/Le Thouron 118
P. Jenniskens Meterik/Quinson 107
K. Jobse Oostkapelle/Lardiers 67
K. Miskotte Harderwijk/Puimichel 47
F. Bettonvil Heesch 29
C. Johannink Denekamp 27
A. Scholten Bussloo 23
M. Betlem Elsloo 14
P.A. Koning Loenen 14
R. Schievink Buurse 14
M. Breukers Hengelo 11
J. de Jong van Lier Denekamp 10
J. van 't Leven Bussloo 8
B.C. Apeldoorn Winterswijk 4
E. van Ballegoy Lheebroek/Puimichel 4
S.J. van Leverink Bakkum 4
J. Nijland Heiloo 4
J. Bruining Appingendam 3
G.S. Cladder Denekamp 2
G.A. Hafkenscheid Heerhugowaard 2
P. van der Veen Loosdrecht 2
L. Bruning Epen 1
P. van Graafeiland Heemstede 1
H. ten Haaf Muiderberg 1
J. Hermans Schaesberg 1
P. Koeyvoets Roosendaal 1
M. Langbroek Voorschoten 1
L. Muytjens Breda 1
W. Nobel Muiderberg 1
D. van den Oudenalder Hilversum 1
U. Poerink Vught 1
M. van Vliet Oostkapelle 1
Table 1: The photographic observers that contributed to this project, the most frequent location of their station in the Netherlands and in France, and the number of multi-station components that were contributed


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