We describe the history of solar-eclipse supervision since the formation of the International Astronomical Union, as the supervising body morphed from a full commission to a subcommission to its current status as an Inter-Divisional Working Group of the Education, Outreach and Heritage Division and the Sun and Heliosphere Division.

This paper discusses my time as IAU General Secretary, 1967–70 and the General Assemblies in Prague in 1967 and in Brighton in 1970. I cover my work with Jean-Claude Pecker, whom I succeeded as General Secretary and with Donald Sadler, who was General Secretary 1958–64. The work of J. Kleczek for the International Schools for Young Astronomers is discussed.

IAU Commission 41 (History of Astronomy) was founded in 1948, and between 1991 and its termination in 2015 this Commission hosted seven different Working Groups (one of which was shared with Commission 40 (Radio Astronomy). In this paper we list the objectives of these seven Working Groups and track their progress. We conclude by evaluating the role that each C41 Working Group played in furthering research on the history of astronomy.

Beginning in year 2000 the IAU undertook a number of initiatives that changed the Union from being primarily an inward-focused organization whose emphasis was the world of professional astronomy, to being more outward looking in engaging with the public. These initiatives included proposing to the United Nations and then leading the International Year of Astronomy IYA 2009, and the formulation of a Strategic Plan that included creation of the Office of Astronomy for Development. Additional programs are being undertaken by the Union that continue to broaden IAU engagement with the public.

After the foundation of the International Astronomical Union (IAU), it took nearly 32 years until Germany became a national member of the IAU. This unfortunate delay was due to both international politics and discussions within Germany (e.g. about the future role of the Astronomische Gesellschaft). The first Statutes of the IAU of 1919 excluded Germany, Austria and other countries from membership for political reasons. When the IAU Statutes were revised in 1931, Germany’s membership was possible, but could not be realized because of financial problems. In the mean time, German astronomers (as individuals) were often able to attend General Assemblies of the IAU as invited participants and to work in IAU Commissions as members. After World War II, Germany became a member of the IAU in 1951, Austria in 1955. In 1962, East Germany was accepted as an additional member. The reunification of Germany in 1990 clarified this situation. Member of the IAU is now one unified Germany.

Continuous regional cooperation is efficient and constructive for long-term development of astronomy, as clearly shown by the great success of ESO in the European Region. The IAU does not formally define its Regions, however they are becoming clear through the Regional Meetings during recent decades. We present some statistics and considerations about five IAU Regions, based on the temporarily assumed geographical distribution of IAU National Members. For further growth of IAU and worldwide astronomy, the role of Asian Pacific, Lain American, and Mid-East & African Regions is essentially important. We can identify three groups; “Super”, “Advanced”, and “Developing” groups of IAU National Members based on the rate of IAU Individual Member per population in each of the National Members. This rate, identical to the number of astronomer per head of population, can be regarded as an indicator of the “strength” of astronomy in each of the NMs, while the number of Individual Members indicates the “size” of astronomical research. We find that the distribution of this rate shows clear differences from Region to Region. Based on this analysis, we propose planning within IAU National Members, each Region and the EC so as to grow from a “Developed” group to an “Advanced” group, as well as to increase the number of NMs. The IAU should encourage and support those efforts by National Members and Regions through the platform of Regional Meetings, the OAD and other possible strategic programmes.

This year 2018 has great historical and current significance for stellar spectral classification. Two hundred years ago in Reggio Emilia, Italy, was born Angelo Secchi, a pioneer of observing and classifying the spectra of stars. At the beginning of the IAU, almost a hundred years ago, one of its original Commissions was entitled the Spectral Classification of Stars, from which was generated Commission 45, Spectral Classification and Multi-band Colour Indices. And seventy-five years ago, was published the system-changing MKK, An Atlas of Stellar Spectra. Through this necessarily brief, historical view we shall recall how spectral classification, supported internationally by the IAU, continually updated its techniques, while remaining anchored to standards. This has ensured that the MK classification process stays very relevant to the initial characterizing of stars in the 21st century era of large spectral surveys.

The USA delegation to the July 1919 International Research Council meeting in Brussels included Joel Stebbins, then professor of astronomy and observatory director at the University of Illinois, as secretary of the executive committee appointed by the National Research Council. Stebbins, an avid photographer, documented the travels of their party as the American astronomers attended the meeting and later toured devastated towns, scarred countryside, and battlefields only recently abandoned. Published reports of the meeting afterward attest to the impression left on the American visitors, and the photographs by Stebbins give us a glimpse through their own eyes. Selected photographs, recently discovered in the University of Wisconsin Archives and never before publicly seen, will be presented along with some commentary on their significance for the International Astronomical Union, which took shape at that 1919 meeting.

“Urania” is a popular Polish astronomy magazine, one of the oldest in the world among present journals of this type. The first official issue was published in 1922, but the origins of “Urania” are even older, as in 1919 and 1920 there were published a few issues of a predecessor of “Urania” with the same title. So we can say that “Urania” and the IAU are of the same age. The role of “Urania” has been changing during these 100 years, but the magazine has been always a very important entity for the astronomical community in Poland, both professional and amateur. Thousands of pages contain an historical record of astronomy in Poland, as well as the progress of astronomy in the world, including IAU activities.

In this paper I discuss the general role of the IAU General Secretary, and reminisce on the XXIst IAU General Assembly in Buenos Aires, Argentina in 1991, where a fire disrupted proceedings on the final days.

Astronomy in Japan has long history and has its own “light”. The foresight of leaders in the early 20th century helped Japan to become a founding member of the International Astronomical Union. In this paper, a brief description will show the growth in its more recent history with particular emphasis on two important issues: large research facilities and women participation. On the ground or above, the large observational facilities are nowadays outside of the land of Japan, not only in terms of physical presence but also the community they serve. Domestic membership of the Astronomical Society of Japan at the same time is expanding, thanks to the increased opportunities for women. Continuing global cooperation with more diverse composition of members are the keys for sustaining the growth to carry the astronomy in Japan with IAU into the next century, and hopefully to another planet.

One hundred years ago, the International Astronomical Union was created, one of the very first Unions dedicated to the advancement of a discipline and the promotion of international collaboration and exchange. In 100 years, astronomy has made huge progress, and the IAU has greatly expanded in volume and purpose. In recent years, it has become more and more active in education, astronomy for development and dissemination of astronomy to a large public.

Even though Italy officially joined the IAU in 1921, Italian astronomers were involved in its birth as early as 1919, when Annibale Riccò, Director of the Astrophysical Observatory of Catania, proposed to the IAU Committee to hold its first General Assembly in Rome. This contribution will analyze the role played by Italian astronomers in the development of the IAU from its foundation to the Second World War. The recent project of reordering of the astronomical historical archives in Italy permits for the first time a more in-depth study of the relations between Italian astronomers and the international scientific community.

During the 100 years of the International Astronomical Union, the worldwide astronomical publications have grown exponentially, converted almost entirely to English, and changed format from observatory publications to journals to online publications. Observatory publications, conference proceedings, and individual theses have nearly disappeared in usefulness for research.

This paper presents my own recollections of the difficult relations that existed between the IAU and a fraction of the public, especially in the USA, following the IAU decision to reclassify Pluto as a dwarf planet at the 2006 General Assembly in Prague, and which ultimately led the IAU to organize the NameExoWorlds international contest to give public names to selected exoplanets and their host stars. In spite of the success of the International Year of Astronomy in 2009, the Pluto controversy continued, and its consequences climaxed during my term (2012-2015), as NASA’s New Horizons probe approached Pluto for a flyby just before the 2015 General Assembly in Honolulu. It was during this period that the IAU launched the NameExoWorlds contest, which also came to a conclusion in Honolulu after over half a million votes were cast from all over the world. While the inside story of how the contest was organized has appeared elsewhere, here I focus on the historical and sociological context that made Pluto such a sensitive issue, especially in the USA, explaining why this contest generated another controversy between the IAU and the New Horizons team. However, after the world-wide success of NameExoWorlds, the IAU and the New Horizons team eventually reached an agreement on finalizing the characterization and names of a number of newly discovered Pluto and Charon surface features (an on-going process), while a new edition of NameExoWorlds is in preparation for the IAU centennial in 2019.

During the last twenty years, due to the extensive help and assistance of the international scientific community, there has been a great success in the development and establishment of new well-functioning and competitive scientific groups specialized in general relativity and relativistic astrophysics in Uzbekistan (Tashkent), Kazakhstan (Astana and Almaty), Kyrgyzstan (Bishkek) and great achievements have been made on the study in Central Asia in relativistic cosmology and astrophysics of compact gravitational objects.

In 1539 the Italian Giovanni Paoli, better known as Juan Pablos, began operating in Mexico City the first printing press that existed in the New World. The first books he printed were religious texts, vocabularies of some indigenous languages of Mexico, and compilations of ordinances and laws. In 1556 followed the Sumario compendioso de las cuentas, a text of arithmetic and algebra that was the first American mathematics book. A year later, he printed the Physica Speculatio by friar Alonso de la Veracruz, a text of Natural Philosophy that dealt with Aristotelian works such as Physics, On the Heavens, and Meteorology. As part of this book, was included the text of geocentric astronomy written during the thirteenth century by the Italian mathematician Giovanni Campano de Novara, entitled Tractatus de Sphaera, where the author discussed, from a geometric perspective, the cosmic structure and the stellar distribution. No doubt this is the first astronomical treatise that was published in the entire American continent, which is why it is emphasized here.

The astronomical community accepts the division of the celestial sphere into 88 constellations, according to what was established by the IAU. In the first Assembly of 1922 the use of Latin names for constellations and their abbreviations was resolved. The pending issue of the limits of the constellations was discussed in the next meeting and Eugène Delporte had the responsibility for the complete theoretical demarcation. For his work, Delporte took into account what was done half a century earlier in the famous work Uranometría Argentina, published in 1877 and 1879, under the supervition of Benjamin Gould. In ths presentation we discusse the situation at the moment when the constellation boundaries were proposed using arcs of RA circles and parallels of declination, choosing them in such a way that they did not deviate too much from those used in the most important celestial atlas of the time, and minimizing the changes of which constellations stars would belong to.

The Czech astronomer František Nušl (1867–1951) was professor of mathematics, practical astronomy and geometrical optics at Prague Charles University. His scientific contribution to astronomy consisted mainly of inventing and constructing of new astronomical and geodetical instruments. Together with his friend Josef Jan Frič, founder of the Ondřejov Observatory, he developed and improved the circumzenithal telescope (1899–1903–1906–1922–1932), a portable instrument with a mercury horizon for determining the geodetic position using the Gauss method of equal altitudes. This instrument won the gold medal at the Exposition Internationale des Arts et Techniques dans la Vie Moderne in Paris in 1937. Nušl, independently of Ernst Öpik, invented the wobbling mirror for determining the velocity of meteors by visual observation, and constructed an unique guiding system for the Ondrejov astrograph etc. The organizational activities of Frantisek Nušl were considerably rich, too: He was one of the founders of the Czech Astronomical Society in 1917, in the years 1922–1948 he served as its president. From 1918 until his retirement in 1937 he was the director of the Ondrejov Observatory, 40 km south of capital city of Prague, lectured astronomy at the Prague university and held many popular lectures including regular courses in radio broadcasting. František Nušl was member of several commisions of international scientific unions; he organized the 3rd General Assembly of IUGG (International Union of Geodesy and Geophysics) in Prague 1927, and in IAU (International Astronomical Union) he was elected as Vice-President in the years 1928–1935. One can conclude that he was the main person who formed the Czech astronomy in the interwar period.

We briefly discuss the history of membership and the current position of Serbia inside the International Astronomical Union. We give an overview of astronomy education, research and public outreach in Serbia. Some statistics are presented concerning the number and gender of BSc, MSc and PhD students that graduated/obtained their degree in astronomy/astrophysics from the Department of Astronomy, Faculty of Mathematics, University of Belgrade. Due attention is paid to the most important scientific/educational institutions in Serbia in which the majority of astronomers are employed as well as various research topics investigated.