Because of unforeseen difficulties, Dr Sinzi, President of the Commission, was not able to prepare this Report. It was then too late for asking the Directors of the almanac offices and the other Members of the Commission for informations. This Report is therefore based on the material just available, and it must be apologized for some lack from which it necessarily suffers. If possible, any omitted facts which appear to be serious, may be included in the Report for the following triennium.

The range of activities of Commission 5 has considerably broadened over the last decade, compared with its originally bibliographical emphasis. This fact is also reflected in the new name of this Commission as adopted at the Montreal conference. The increased production of astronomical data, the growing role of data centers in the organisation and retrieval of information, as well as the editorial and bibliographic processing of the large number of primary papers have indicated the need for new and more efficient coordinative guidelines. Several documents have been published and are under consideration, or are in preparation, for the agenda at the IAU General Assembly in 1982.

The Commission has been fortunate in being able to continue its work during the last triennium with a minimum of effort, and thanks for this should go largely to the Director of the Bureau, Dr B.G. Marsden, for his untiring dedication, as well as to the Smithsonian Astrophysical Observatory for its general support. If any question has arisen, it was where the line should be drawn between paid and unpaid contributions to the Circulars. This involves a somewhat delicate balance of interests between, on the one hand, the encouragement given to certain types of observations which have traditionally been published in the Circulars, (e.g. accurate positions of comets), and, on the other, the income on whi h the continued successful operation of the Bureau depends. The position will therefore have to be kept under review at all times. At present all evidence points to general satisfaction with current policy.

In the past three years progress of celestial mechanics research was as rapid as in the previous decade. In fact now new theories of planetary and lunar motions which have nearly the same accuracy as those of the most precise observations have become available after a decade effort and new thories of some of natural satellite motions have been developed by several authors. Many papers on artificial satellite motions from several aspects were still published and more precise expressions for relativistic effects were derived.

The present report covers the period from 1 January 1979 to 31 December 1981. This period includes the first eight months (to 26 August) of the year 1979, which was part of the period in office of the previous Executive Committee; it does not include the first eight months of 1982, still the period of responsibility of the present Executive Committee (to 27 August 1982).

This report includes a summarized financial report for the calendar years 1979, 1980 and 1981 and a budget proposal for the calendar year 1982, closing the 3-year budgetary period 1979-1982.

This report summarizes research on solar activity over an almost three-year period from January 1, 1979, till the end of June 1981. In preparing this report we respected the advice of the I.A.U. Executive Committee to cover the highlights of work carried out in the field of solar physics relevant to our Commission, and avoiding double work. Only a limited space was made available for our Commission. Given this restraint we tried to produce a comprehensive review. With great pleasure I appreciate the excellent cooperation of the members of our Executive Committee in the preparation of this report.

The report of Commission 12 presented here covers the parts of the field of solar physics other than those directly related to solar activities which, in our view, are the time-dependent phenomena inherent to solar active regions to be covered by Commission 10. From the sub-fields in the domain of Commission 12, the Organizing Committee selected six topics of special interest and invite six researchers to prepare reviews. Topics selected and reviewers are (1) Variations of Total Solar Irradiance ( Dr. R. C. Willson, Jet Propulsion Laboratory ), (2) Solar Global Oscillations ( Dr. E. Fossat, University of Nice ), (3) Magnetic Activity and Rotation in the Sun and Stars ( Dr. R. W. Noyes, Harvard University ), (4) Photospheric Magnetic Concentration and Related Problems ( Dr. H. C. Spruit, Max Planck Institut fur Astrophysik ), (5) Coronal Loop Structure and its Heating ( Dr. E. Priest , University of St. Andrews ), and (6) Coronal Transients ( Dr. E. Hildner, NASA Marshall Space Flight Center ). Of course it is not that there were no important contributions to the progress of sub-fields of solar physics other than those presented here. It was our consensus, however, that we should adopt this method since a complete coverage of works appearing across the entire field is no longer possible because of the rapid increase in the number of works in the expanding field of solar physics when severe page limitations exist for the IAU Reports.

The rapid expansion during the past few years of the spectral region accessible to astronomical observers, from gamma rays to the radio region, has resulted in a corresponding expansion of the need for a wide variety of atomic and molecular data. Included are needs for accurate wavelengths, atomic and molecular energy levels, and transition probabilities. The continually improving resolution that has been attainable has resulted in the requirement of improved insight into line broadening mechanisms of various types. This expansion has placed an increasing premium on data compilation and dissemination, so that available information can be made readily available to potential users. Among the numerous compilations that have appeared might be mentioned the important National Bureau of Standards Bibliography on Atomic Levels and Spectra, which is up-dated periodically via successive supplements, and the NBS compilation and bibliography by the Data Center on Atomic Transition Probabilities. Several compilations or bibliographies on collision cross-sections are now available, such as that published by the Information Center at JILA. In the field of molecular spectra there has appeared the very comprehensive “Constants of Diatomic Molecules” by Huber and Herzberg. Other useful compilations are referred to in the reports of the five Working Groups that appear below.

The illness which prevented Dr. N. Richter from presiding over Commission 15 sessions in Montreal proved fatal on November 26, 1980.

Books published since 1978 dealing with the subject matter of Commission 15 are: (1) Comets and The Origin of Life, ed. C. Ponnomperuma, 1981, D. Reidel pub. Co., Dordrecht, Holland (designated C. P. Colloq. in Report); (2) Comets, ed. L. Wilkening, Univ. Arizona Press, 1982 (designated Comets, 1982 in Report) contains invited reviews of Tucson, IAU Colloquium No 61, “Comets” Gases, Ices, Grains, Plasma”. Contributed papers will appear in a volume of Icarus. Papers dealing with cometary and asteroidal orbits appear in IAU Symp. 81, 1979 and with cometary grains and meteorites in IAU Symp. 90, 1981. Proceedings of Workshops are: (1) “Experimental Approaches to Comets”, ed. J. Oro, 1978, Lunar and planetary Institute, Pub. 361; (2) “Modern Observational Techniques for Comets”, eds. J. Brandt et al., 1981, JPL Pub. 81-68, NASA.