The period of this Report includes 1984 January 1, the date which was probably the most drastic caesura in the history of astronomical almanacs. It seemed, therefore, appropriate to concentrate here to the general aspects rather than to describe the works going on at the particular almanac offices. It is, however, hoped that the past years with their developments and changes will be followed by a period of consolidation and continuity. This would be also of great benefit for the users of the almanacs who still need some time for getting accustomed to so many innovations.

The report period 1982-84 was characterized by an again increased volume of material processed in data and abstracting centers, and by a growing clientele particularly of online services. The Working Groups of Commission 5 seek continued consultation with research object commissions so that the advanced documentation technology be efficiently employed toward specific demands of subject areas as to indexing, tagging, comprehensive, selective and inter-discliplinary retrievals. The guideline library for these purposes has been augmented by the First Dictionary of the Nomenclature of Celestial Objects by A. Fernandez, M.-C. Lortet and F. Spite (Astr. Astrophys. Suppl. 52 no.4, 1983) and by the Guide to the Presentation of Astronomical Data by G.A. Wilkins (CODATA Bull.46 1982); a new draft of the IAU Style Manual is before the IAU EC.

The bulk of the Commission’s work has, as in previous years, been carried out most efficiently by the I.A.U. Bureau, especially by its Director, Dr. B.G. Marsden.

Celestial Mechanics has undergone, in the past three years, a considerable development that has been marked by a significant increase of published papers and by the recent organization of several specialized colloquia or symposia. The reasons of this increase of interest may be found among the following circumstances:

1. - The discovery of new dynamical situations in the Solar system: ellipticity of ringlets, shepherd satellites.

2. - The increase of interest in the problem of the dynamical evolution of the solar system or of its subsystems.

3. - The present necessity to include relativistic effects in the theory of motion of celestial bodies.

4. - New promising results in the analysis of the properties of dynamical systems.

The president thanks those members contributing material to this report. The volume of the material necessitated some editing, but no substantive omissions occurred. Whenever available, AAA numbers are used in lieu of complete titles of publications to help conserve space.

IAU Symposium No. 109 Astrometric Techniques, was held in Gainesville, Florida in January 1984. Although the Proceedings of that meeting are not now available (January 1935), ccmnission members and other interested parties are urged to secure access to that voline when it appears since so many facets of the commission’s work are addressed therein.

Between the Patras and New Delhi General Assemblies no meetings were directly sponsored by Commission 9 because the discipline was amply covered by the following:

• - “Eighth Symposium on Photoelectronic Image Devices,” Imperial College (London) 5-7 September 1983 (B. L. Morgan, Ed., Academic Press, London, 1984).

• - “Advanced Technology Optical Telescopes II” Imperial College, 5-7 September 1983.

• - “Instrumentation in Astronomy V” 7-9 September 1983 (A. Boksenberg and D. Crawford, Eds., Proc. SPIE 415).

• - IAU Symposium No. 109: “Astrometric Techniques,” 9-12 January 1984, Gainsville (Florida).

• - “Astronomical Photography 1984,” Edinburgh, 4-6 April 1984 (E. Sim and K. Ishida, Eds., Number 14 of Occasional Reports of the Royal Observatory, Edinburgh).

• - “IAU Colloquium No. 79: “Very Large Telescopes, Their Instrumentation and Programs,” Garching bei München, 9-12 April 1984 (M. H. Ulrich and K. Kjär, Eds.)

In preparing the present report, which covers the period July 1, 1981, to June 30, 1984, close collaboration has taken place between Commissions 10 and 12, the two solar commissions, in order to avoid duplications and to insure that pertinent subjects are treated. The reader is referred to the report of Commission 12 for further solar topics. It is a pleasure to acknowledge the excellent work of the reviewers who wrote the different sections of this report, and all the members of the commission who provided information on research to be included.

Work begun during the Solar Maximum Year (SMY) (1980-1981) was the focus of several sympsoia and workshops starting in March 1981 with the International SMY Workshop in Simferopol, Crimea (Obridko 1981). Results of the Annecy SMY Workshop (Annecy, France, October 1981) were presented in May 1982 with later work presented at the first SMY symposium (ĸvestka et al. 1982) in Ottawa, Canada. A special symposium for the Study of Travelling Interplanetary Phenomena was held in Maynooth, Ireland, in August 1982 (Shea et al. 1984). Another SMY workshop was held in November 1983 in Kunming, China (Chen 1984), and the second SMY symposium was held in June 1984 in Graz, Austria (Simon 1985). The scientific progress of the SMY is detailed in the above-mentioned publications and in the 1982 U.S.-Japan Seminar “Recent Advances in the Understanding of Solar Flares” (Kane et al. 1983). Highlights of the work of the SMY’s Flare Build-Up Study, Study of Energy Release in Flares, and Study of Travelling Interplanetary Phenomena are presented below.

The ongoing research carried out by the solar community has been reported in the proceedings of several recent symposia, seminars and workshops, as well as in scientific journals (Kane et al. 1983, Švestka et al. 1982a, Shea et al. 1984, Kundu S Woodgate 1984, Simon 1984). We summarize here some of the novel results with reference to flare research as far as SMM data analysis is concerned. Understanding of impulsive phase phenomena was one of the primary goals of the SMM. The early reports from the analysis of the first ever obtained high-resolution images in the <30 keV energy range stressed the fact that some flares showed hard x-ray (HXR) bright sources at the feet of coronal loops (Hoyng et al. 1981a, b, Machado et al. 1982, Duijveman et al. 1982), the so-called HXR “footpoints,” favoring the thick-target beam mechanism for the production of HXRs, and indicating acceleration efficiencies >20% during the early impulsive phase. This phenomenon was shown to be accompanied by soft x-ray (SXR) line broadening, indicative of strong turbulence, and the immediate appearance of blue shifted spectral lines, which shows that plasma heated to >10-1 K rises from the footpoints of loops with velocities to 300 km s-1 (Antonucci et al. 1982, Antonucci et al. 1984a). This result provides a strong indication of the chromospheric evaporation phenomenon, which has been confirmed in analyses of combined SXR and Ha observations (Acton et al. 1982, Gunkler et al. 1984).