In October 2020 the South African Astronomical Observatory celebrated 200 years of existence as an astronomical observatory by organizing a virtual symposium “Beyond 200 Years of Astronomy”. The theme of that symposium covered a wide range of topics, among which African ethnoastronomy and indigenous knowledge, history of astronomy in Africa, astronomy in recent decades, and astronomy and society. Focus Meeting 6 at the XXXIInd General Assembly centered on people, instruments, and projects during the past two centuries – that is, the period since the establishment of the South African Astronomical Observatory in 1820.

We explore the opportunities and challenges of transferring Boyden Station from Peru to South Africa, the partnerships between the local government and American astronomers, and the research carried out by the transported instruments, which were paired with those in the northern hemisphere. The Boyden Observatory site, though still a professional observatory operated by the Department of Physics at the University of the Free State, also houses a Museum. The 60-inch reflector telescope is the third largest on the African continent, and is used by postgraduate astrophysics students.

Next, we describe a project initiated by the Magaliesberg Association for Culture and Heritage in collaboration with the Tshwane University of Technology in South Africa. The endeavour is unique in combining astronomical history and African archaeology, viz., the occurrence of two adjacent heritage sites on the university rural property, named “Toppieshoek”, close to Hartbeespoort Dam. One site is the former Leiden University Observatory Southern Station, the other an Early Iron Age archaeological site dating from AD 350. The former recalls 20th-century international scientific collaboration, the latter reveals the first arrival of Black immigrants into South Africa.

Whereas the focus of South African astronomy from the mid-eighteenth to the mid-nineteenth century was on measuring the size and the shape of the Earth, the subsequent century focussed on the size and the shape of our Galaxy, involving research that cannot be properly undertaken from the northern hemisphere.

John Herschel, a gentleman of independent means, was the first to go beyond positional astronomy. Others followed soon, such as Alex Roberts, another independent researcher who provided pathbreaking insights on eclipsing binary stars, and helped establish the early cosmic distance ladder.

The cosmic distance scale was wrong until the 1950s, when it was suddenly doubled when David Thackeray and Adriaan Wesselink found RR Lyrae stars in the Magellanic Clouds, but much fainter than expected. The world’s newspapers broadcast the news that the universe was at least twice as big as had been hitherto believed.

The Cape Photographic Durchmusterung (CPD) was devised by Sir David Gill at the Royal Observatory at the Cape in 1882 and was commenced in 1885. Over 3 000 plates of the southern sky were exposed, reaching about magnitude 9.5. The CPD facilitated the Carte du Ciel project – launched in 1887 by Paris Observatory – that aimed at the production of the most accurate astrographic map and catalogue ever made. Today, the South African Astronomical Observatory (SAAO) owns more than 18 000 photographic plates exposed since 1843. In 2023 the Shanghai Sheshan Astronomical Observatory signed an agreement with SAAO to cooperate on the digitization of all SAAO plates in the near future. Astronomical plates taken in South Africa are also preserved in the Leiden Observatory’s plate archive. This collection began in the late nineteenth century and currently contains nearly 50 000 plates – a valuable heritage that urgently needs to be preserved.

The Royal Observatory at the Cape of Good Hope, later the South African Astronomical Observatory, was authorized in 1820, building it in a colony with little skilled labor was another matter. Keeping the Cape observatory going and productive required heroic efforts through much of the nineteenth century, as a crushing burden of astrometric work overtaxed the small trained staff available. All that would change when David Gill revolutionised what had become an astronomical backwater, leaving the Royal Observatory in 1906 with quadrupled staff, modern instruments and methods. Gill was the first to take the initiative to employ women at the observatory. The institution pioneered the production of stellar catalogues by photography, and advanced precision photometry. The Radcliffe Observatory detected RR Lyrae variables in the Magellanic Clouds, which led to a revision of Hubble’s distance scale. This was followed by the introduction of radio, infrared and gamma-ray observations.

In 1751 Nicolas-Louis de La Caille came to the Cape to measure the length of a degree of latitude, but despite meticulous surveying work and laborious data reduction, his results were inconsistent with those obtained in France: the shape of the Earth in the southern hemisphere differed from the results obtained in the northern hemisphere. In 1840 Thomas Maclear undertook the verification of La Caille’s arc, and reported in 1866 that La Caille’s measured latitudes were affected by deviations from the vertical by mountain masses at Table Mountain and Klipfontein. La Caille’s measurement of one degree of latitude became the basis of the South African trigonometric system, and Maclear’s chain of triangles became the backbone of the entire South African Geodetic System. Led by David Gill, this chain was extended to the East and to the North covering an amplitude of 104° along the 30th meridian, ending in Cairo.

In this speech, I review briefly the main achievements and contributions of Dr. Barbuy for the development and consolidation of the brazilian astronomy.

Between 1621 and 1626, the soldier-historian Philip O’Sullivan Beare authored treatises to motivate Catholic powers toward greater intervention in Ireland, and to defend his country’s honor more generally. Moving beyond political theology, the author’s unfinished manuscript Zoilomastix incorporated natural history and astronomy. The current article draws attention to a previously overlooked fragment wherein the Irishman considered contemporary debates on the structure of the heavens. It first considers the material history of the fragment, before exploring the influence of continental pedagogic and military networks upon the author. The paper then presents evidence of O’Sullivan Beare’s adherence to Thomist, Bellarminian cosmology, and of his disagreement with Clavius and Galileo, via Jacques du Chevreul’s 1623 commentary on Sacrobosco’s Sphere. Contrasting the fragment’s contents with the cosmogony published in the author’s Patritiana decas (1629), it demonstrates that these exegetic readings were part of the author’s wider strategy for “making truth” amidst shifting political, confessional, and cosmological paradigms.

The Greenwich Prime Meridian is one of the iconic features of the Royal Museums Greenwich. Visitors to the Museum even queue up to pose with one leg on either side of the Line. Yet, the Airy Transit Circle, the instrument that defined the meridian, is almost always excluded from these photographs. This paper examines how the instrument has become hidden in plain sight within the stories of Greenwich Time and Greenwich Meridian, as well as within the public imagination, by providing an analysis of the instrument’s transformation from a working astronomical instrument to a museum object. The paper highlights the gradual decoupling of the instrument from narratives of Time and Longitude, which resulted in the Line’s popularity overshadowing the instrument that defined it. By doing so, the paper aims at showing the symbiotic relationship between the materiality of the instrument and the meridian line that it defined. Approaching the instrument through the lenses of object biographies, the paper raises the question of whether the life of the instrument came to an end once operations with it were terminated. The analysis of the Transit Circle’s life reveals that it reached its end multiple times, which shifts the emphasis away from a single and ultimate end of scientific objects to a process of gradual downfall, during which they can “end” several times. In addition, through the object biography approach, the Transit Circle no longer appears as a dead object reaching an afterlife within a museum setting. Instead, the approach demonstrates that, though the instrument can still be restored to an operational order, doubts about its accuracy, and its relevancy to today’s astronomical methods, have led the instrument to be considered obsolete, transforming it into a museum object on display.

In the context of the European Middle Ages as the period roughly covering from the 5th to the 15th centuries, the astronomical records are rarery found in scientific treatises. At least, not until the 15th century. A few surprinsing examples in which the observations were recorded in a particularly original way on stone are found. In this poster we will shortly review the only four cases in which this occurred in Europe.

Galaxy Forum (GF) South America 2020, was held virtually on December 8, 2020 on the opening eve of IAU 367 by the International Lunar Observatory Association (ILOA Hawai’i) with the support of the Instituto de Tecnologías en Detección y Astropartículas (ITeDA, CNEA-CONICET-UNSAM) and IAU. Galaxy Forum is an education and outreach program sponsored by ILOA, an interglobal enterprise incorporated in Hawaii as a non-profit organization to expand human knowledge of the Cosmos through observation from our Moon and to participate in internationally cooperative lunar base build-out.

As a IAU-367 associated event, Galaxy Forum featured comments by Dr. Beatriz Garcia and presentations by ILOA Director Steve Durst (ILOA Hawai’i, USA), Marcelo Colazo (CONAE, Argentina); César Gonzalez García (CSIC, Spain); Li Geng (NAOC, China); Santiago Paolantonio (Córdoba Observatory, Argentina) and Margarita Safonova (IIA, India). In this contribution, the overview of the contributions permits an approach to the GF interests.

The Night-Sky Observation Program (POC, acronym in Portuguese for Programa de Observação do Céu) is the most traditional education activity run by the Museum of Astronomy and Related Sciences (MAST), located in Rio de Janeiro, Brazil. The activity starts with a brief talk about the astronomical objects available for visibility and is followed by the sky observation with MAST’s telescopes, one of them being over a century old. A study conducted in 2015 pointed out that its participants perceive the historical value of the old refractor and declare that the activity brings them feelings of wonderment. These perceptions and declarations have motivated us to conduct a new study to identify and exchange experiences with institutions worldwide that also use historically valuable telescopes in their night-sky observation activities with the public. With the goal of gathering information from these institutions and making it into a guide, an online survey with open and close-ended questions was launched in late 2017. Nearly eighty institutions from all continents answered our questionnaire. The data collected are vast and rich and not only tell about the passion of those mediating such activities, but also the history of astronomy itself.

The aim of this work is to provide new information about the history of astronomical science and the efforts of the people that have enriched our discipline, often coming from anonymity. Here we compile the attempts made in our country to prove the theory of General Relativity through experiments that, as they were without success, fell into oblivion.

The IAU was founded in 1919 “to facilitate the relations between astronomers of different countries where international co-operation is necessary or useful” and “to promote the study of astronomy in all its departments”. These aims have led the IAU throughout the century of its existence, but the way it has tried to fulfil them has changed. We have tried to trace the changing role of the IAU in the international astronomical community through the twentieth century and into the twenty-first. The IAU has striven – occasionally struggled – to protect international scientific cooperation across the deep political divides that characterized the 20th century, while maintaining an important function in the context of the rapidly evolving science itself and the changing fabric of institutions involved in astronomy. We especially argue how the emphasis of the IAU’s activities has shifted from the first aim – facilitating collaboration by organizing meetings and defining common standards – to the second aim: promoting astronomy by outreach and development programs.

2017 marked the 130th anniversary of the start of the Carte du Ciel project, an ambitious proposal by the Paris Observatory to map the entire sky using photographiy, which required the joint work of numerous observatories in the world. For this endeavour, an impressive organization was designed that included congresses, commissions and publications, which lasted through many years. The Carte du Ciel finally became one of the immediate antecedents of the International Astronomical Union, which in 2019 celebrates its first century. In Latin America, the observatories of Santiago de Chile, La Plata and Rio de Janeiro, the Argentine National Observatory and the Tacubaya Observatory, in Mexico, were involved in the project. In this presentation, we present part of the history of the failures and successes of one of the most important collaborative astronomical projects on the planet.

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.

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 first hundred years of the IAU have witnessed scientific and technological progress in astronomy beyond anything imagined at the time the IAU was founded in 1919. What will the next hundred years bring? How do we engage with other sciences, now that our field is becoming more multidisciplinary? How do we convince governments to continue funding our field, in particular the ever more powerful telescopes? And how do we continue to inspire and involve people worldwide in our exciting adventure through space? A brief forward look into the next decade and beyond is presented, with some challenges highlighted.