Astronomy isthemostancientsciencehumanshavepracticedonEarth. Itisascienceofextremesandoflargenumbers:extremesoftime–fromthe big bang to in?nity –, of distances, of temperatures, of density and masses, ofmagnetic?eld,etc.Itisasciencewhichishighlyvisible,notonlybecause stars and planets are accessible in the sky to the multitude, but also - cause the telescopes themselves are easily distinguishable, usually on top of scenic mountains, and also because their cost usually represent a subst- tialproportionofthenation’sbudgetandofthetaxpayerscontributionsto that budget. As such, astronomy cannot pass unnoticed. It touches on the origins of matter, of the Universe where we live, on life and on our destiny. It touches on philosophy as well as on religion. Astronomy is the direct c- tactofhumankindwithitsoriginsandtheimmensityofuniversalnature.It is indeed a science of observation where experimentation is practically - possible and which is ruled by mathematics, physics, chemistry, statistical analysis and modelling, while o?ering the largest number of veri?cations of the most advanced theories of fundamental physics such as general r- st ativity and gravitation. At the beginning of the 21 century astronomy is clearly a multidisciplinary activity touching on all aspects of science. It is therefore logical that in the past and still now, astronomy has attracted the most famous scientists, be they pure observers, mathematicians, physicists, biologists, experimentalists, and even politicians.

The principal purpose of IAU Colloquium No. 35 was to discuss those aspects of the techniques of the compilation, evaluation, and distribution of data that are common to astrometry, photometry and spectrometry of stars and stellar systems. In the announcement of the Colloquium, it was suggested that there would be special emphasis on the techniques of quality control, and on the standards for the presentation of numerical data in both printed and com puter-readable form. As the meeting progressed it became clear that the lack of a standard, unambiguous system for the identifi cation of stellar objects was a source of much confusion and inefficiency in the use of existing data files. This and other such matters were the subject of further discussions by Commission 5 at the General Assembly of the International Astronomical Union (IAU), which was held at Grenoble during the following fortnight, 24 August - 2 September 1976. The proposal for the Colloquium was prepared by J. Jung, who was then Director of the Centre des Donnees Stellaires at Stras bourg, and G. A. Wilkins, Chairman of the IAU Working Group on Numerical Data, and was accepted by the IAU Executive Committee on the recommendation of the President of Commission 5, with the support of Commissions 25, 29 and 45. The Scientific Organising Committee consisted of W. Fricke, B. Hauck, C. Jaschek, J. Jung, B. Kukarkin, P. Lacroute, A. Underhill and G. A. Wilkins (Chair man). The Local Organising Committee consisted of A.

A concise, organised reference that explains the functions and configurations of astronomical instrumentation. It provides an overview of aspects of astronomical instrumentation from principles of general optics and optical design to optical manufacturing and systems engineering.

The idea of this Colloquium came during the XVIIth General Assembly of the I. A. U. at Montreal. The meeting was organized under the auspices of I. A. U. Commission 5 (Documentation and Astronomical Data). The Scientific Organizing Committee consisted of C. Jaschek (chairperson), O. Dluzhnevskaya, B. Hauck (vice chairperson), W. Heintz, P. Lantos, Th. Lederle, J. Mead~ G. Ruben, Y. Terashita, G. Wilkins. The members of this Committee are to be thanked for their devotion to the organization of what turned out to be a very successful meeting. The program was organized so as to cover most of the aspects concerning work with machine readable data. In a certain sense it is the develop ment of the subjects of I. A. U. Colloquium 35 "Compilation, critical evaluation and distribution of stellar data" held at Strasbourg in 1976. The meeting was opened by welcoming addresses delivered by Dr A. Florsch, Director of the Strasbourg Observatory, Prof. H. Curien, President of the European Science Foundation and Prof. W. Heintz, President of I. A. U. Commission 5. The sessions were devoted to the fol lowing subjects : Existing data centers, Data networks, New hardware, Recent software developments, Bibliographical services, Copyright, Editorial policies and nomenclature, Data in astronomy and Data in space astronomy. The different sessions were chaired by G. A. Pilkins, J. Mead, S. Lavrov, W. Heintz, P. Lantos, M. McCarthy, J. Delhaye and G. Westerhout. On July 9. Dr A.