The appended reports of the directors of the national ephemeris offices provide a record of the current activity in the publication and preparation of astronomical ephemerides, including those published for use by navigators and surveyors and those prepared for astronomers whose special needs are not met in the printed almanacs. A brief review of the relevant work of other institutions and individuals is also given in the appendix. The reports also cover to some extent activities in positional astronomy and celestial mechanics (i.e. in the fields of interest of Commissions 7, 8, 17, 19, 20 and 31). This report is therefore restricted to reviewing, firstly, the action that has been taken on matters raised at and since the 1967 meetings of the Commission and, secondly, the matters that will require attention at and after the 1970 meetings.

Before that review, it is appropriate to pay tribute to the memory of that almost legendary astronomer, Gaston Fayet, who died on 27 December 1967 at the advanced age of 93. As member of the Bureau des Longitudes responsible for the production of the Connaissance des Temps from 1930 to 1961, and President of Commission 4 from 1938 to 1952, he contributed greatly to our subject, in addition to his researches in other fields particularly in respect of the minor planets.

During the period under review two issues of the Astronomical Yearbook of the U.S.S.R. for the years 1971, 1972 have been published, and that for 1973 is in preparation. The positions and proper motions of the stars are in the FK4 system as recommended by Commission 4 in 1961. Further, as recommended at the meeting in Hamburg in 1964 (Trans. IAU, 12 B (1964), 105,1966) the IAU System of Astronomical Constants has been introduced into the tabulations of the day numbers, solar and lunar eclipses, ephemerides for physical observations of planets, and the factors S &C. The corresponding differential corrections to the Moon’s ephemeris as well as re-calculated eclipse data for 1971 have been tabulated separately in the Appendix to the Yearbook for 1971. As from the edition of the Yearbook for 1972, the lunar ephemeris j = 2 will be published in accordance with the recommendations adopted in Prague in 1967.

The regular publication of the ephemeris of the lunar crater Mösting A has been continued in the editions of the Yearbook mentioned above.

Fundamental ephemerides of the Sun, Moon, and planets have been printed in full conformity with the first part of the Astronomical Ephemeris circulated in advance by H. M. Nautical Almanac Office, Royal Greenwich Observatory.

The operation of the Central Bureau for Astronomical Telegrams, thanks to the diligence of its Director and his collaborators, has continued to remain relatively tranquil and quite effective since January 1968, following the methodology established by the previous Director, Dr Owen J. Gingerich. Financial problems, temporarily at least, seem not to be of major concern. The effective subsidy by the Smithsonian Astrophysical Observatory has been reduced almost to a tolerable level. Policy with regard to the content of the Circulars, however, deserves continuing surveillance by the subscribers.

1. Formal Opening. The President spoke a few words of welcome to the Members of the Union, invited participants and their guests, representatives of Adhering Countries, representatives of sister Unions and other organizations, and formally declared open the first session of the fourteenth General Assembly of the Union.

The most exciting feature of contemporary celestial mechanics is the close interaction with three of the most dramatic engineering achievements of our time: the electronic computer, artificial celestial objects, and the precise measurement of distances in the solar system. The last two provide new information for and make new demands on celestial mechanics and the former provides an effective means of response. These developments have also stimulated people with backgrounds other than celestial mechanics to make contributions in the field.

Since the last meeting of the Union, the use of the computer for literal theoretical developments has become effective and widespread.

The creation of artificial celestial objects not only requires the services of celestial mechanics but provides the means of obtaining new measurements that may throw light on the physical laws that govern the motion of celestial objects. In other words, we can now perform experiments as well as observe.

The Chairman referred to the General Secretary’s motion made at the first session and put to the vote of the General Assembly the new Statutes and By-laws of the International Astronomical Union, as proposed by the Executive Committee. The Statutes and By-laws were adopted by show of hands of the official representatives of Adhering Organizations.

It is with deep regret that we mention the death, on 15 July 1969, of Prof. Dr G. Demetrescu who has done so much for the development of Astronomy in Roumania.

This report is based on letters received from members of the Commission, whom I wish to thank most cordially.

The most important events in the development of positional astronomy during the three past years were:

1. (1) The construction and use of new types of astronomical instruments based on new techniques, and

2. (2) The collective observations of large numbers of stars, especially in the Southern hemisphere on the basis of international cooperation.

At the USNO a design study for a ten-inch automatic meridian circle (ATC)was completed in 1968. Construction and installation should be completed by the end of 1970. A modified Cassegrainian optical system with a Cer-Vit primary mirror is being used. For some other important parts of the instrument new materials will also be used. At each end of the horizontal axis of the instrument Inductosyns will be mounted.

An Inductosyn system for digital readout of the pointing angle of the telescope was installed on the six-inch transit circle of the USNO in 1967 for testing and calibration. An IBM-1800 data acquisition and control system was on line with the same instrument.

Le présent rapport ressemblera peu à ceux présentés aux précédentes Assemblées Générales de l’Union; d’abord en raison des prescriptions du Comité Exécutif concernant la limitation du texte, la suppression des références bibliographiques et la latitude laissée au Président dans la conception même du Rapport; ensuite parce qu’il est apparu que la Commission 9 avait un rôle et une position assez différents de ceux de la plupart des autres Commissions et que l’un des points auxquels il convenait de s’attacher était précisément le re-modelage de son activité.

Toutefois, un certain nombre de membres de l’Union ayant bien voulu résumer l’activité de leurs Institutions ou de leurs pays dans le domaine de l’instrumentation astronomique, leurs contributions trouveront place dans le présent Rapport et fourniront ainsi aux membres de l’Union une information non exhaustive mais cependant des plus utiles, en attendant que soit mise au point une nouvelle forme de documentation.

Enfin, l’un des groupes de travail de la Commission - sur les Tubes à images - ayant poursuivi son travail de coordination et d’information comme par le passé, un rapport spécial sur son activité figurera à la suite du Rapport Général de la Commission 9.

Bien que ce groupe n’est pas été formellement dissous, on doit constater qu’à part une séance lors de l’Assemblée Générale de Hambourg, aucune activité dans le cadre de l’UAI ne s’est manifestée dans ce domaine depuis le Symposium No. 19, tenu à Rome en 1962. Cette réunion répondait à un besoin et le volume de ses Comptes-Rendus a suscité un intérêt certain. Mais au-delà, chacun des groupes intéressés à une prospection a organisé son travail selon ses propres conceptions, en fonction des conditions géographiques qui lui étaient fixées et des moyens matériels mis à sa disposition. Il en résulte que si les méthodes d’évaluation de la qualité des images ont été quelque peu passées au crible de la critique internationale, peu de progrès ont été faits dans le sens d’une comparaison significative à l’échelle mondiale entre des sites inclus dans des campagnes de prospection différentes. Force est bien de regretter ce non-aboutissement, tout en accordant aux responsables des divers opérations l’excuse du délai généralement limité qui leur est imparti, et l’impossibilité d’attendre la mise au point d’une normalisation internationale. Un “groupe interne” de la Commission 9, au sens défini dans la première partie de ce Rapport, pourrait se consacrer à cette importante question.

Un article de synthèse a été publié par Kent Ford en 1968 (1). De plus, le 4ème Symposium international sur les récepteurs photoélectriques d’images s’est tenu à Londres en Septembre 1968 et les comptes rendus des communications paraissent actuellement (2); il y sera fait référence par la mention (AE, page).

Il est espéré que les travaux omis involontairement et les développements nouveaux pourront être présentés lors des séances de la Commission 9 à Brighton.

Le rapport considère les trois types principaux de récepteurs: ceux qui emploient l’électronographie, ceux qui utilisent un écran fluorescent (convertisseurs d’images) et enfin les appareils de télévision.