For over a century, the Carlsberg Foundation has consistently put Danish astronomy ahead of the pack. On this basis, Denmark will no doubt similarly make its mark on the frontiers of astronomy when the European Southern Observatory’s (ESO’s) new mega-project, the 39m European Extremely Large Telescope (E-ELT), goes into operation in 2025. Johannes Andersen, a Danish astronomer with 50 years of experience in science and organisation, here describes how the Carlsberg Foundation during many critical times has come Danish astronomy to the rescue. His story shows how Danish astronomy has flourished through a century of sustained support by the Foundation. The Danish 1.54m telescope at ESO’s observatory on La Silla, Chile, silhouetted against the centre of the Milky Way Galaxy. Photo: © Zdenek Bardon, ProjectSoft, Czech Rep. Astronomy is the most global of basic sciences: One universe surrounds us all, and astronomers observe it at all wavelengths from around the globe. Astronomy has often spawned significant technological and educational developments, but it is essentially a non-profit, peaceful endeavour. Therefore, it is remarkable that over the last century and despite an unfavourable climate, Danish astronomy has flourished as an internationally renowned front-line science. In no small measure is this due to the far-sighted, resolute, and consistent support of the Carlsberg Foundation, which has often been decisive at critical moments through this long period and several generations of personalities on both sides. In simple terms: without the Carlsberg Foundation, Denmark would have been invisible on the world map of astronomy, while today it enjoys a reputation unequalled for centuries. This unique story deserves to be told. The following highlights are based on fifty years of personal first-hand experience through thick and thin. A Glorious Past As a young nobleman living with his uncle in Skåne (now southern Sweden), Tycho Brahe (1546 – 1601) discovered a ‘new star’ in 1572. This made him a world-famous astronomer, who built two highly advanced observatories. Ole Rømer (1644 – 1710) was invited to Paris in 1672 – 1681 by the French astronomer Jean Picard and there discovered the finite speed of light. His versatile practical talents later earned him a long career as a civil servant. Danish astronomy acquired international fame in the 16th and 17th centuries with the towering figures of Tycho Brahe and Ole Rømer. The former became a celebrity overnight by discovering a ‘New Star’ (a supernova) in 1572, a phenomenon that shook the Catholic world to its foundations, as it demonstrated that the stellar sphere does not remain the same for all eternity. Tycho Brahe also maintained a programme of steady improvement and technical innovation of his observing instruments, which led to the precise stellar and planetary positions that Johannes Kepler used to derive his laws for the orbits of the planets – the Copernican revolution. In turn, as a young ‘postdoc’ in Paris, Ole Rømer demonstrated that the speed of light is finite – another profound scientific revolution. Each discovery had undoubtedly merited a Nobel Prize today. Both scientists could also have used the support of a Carlsberg Foundation: Tycho Brahe fell into disfavour with the sovereign king and died in exile in Prague; in contrast, Ole Rømer’s multiple talents as a problem solver and administrator did secure his career, but to the detriment of his scientific work. After these two giants, Danish astronomy went into hibernation for two centuries. New Light at the End of the Tunnel In 1907, the Swedish astronomer Elis Strömgren accepted the professorship in astronomy at the University of Copenhagen. He was a famous expert in calculations of celestial mechanics and orbits in the Solar System, but had little interest in observational work (and the existing Observatory was situated in central Copenhagen). He was also a prominent, internationally oriented scientist with a vast network of personal contacts, which he during both World Wars and the years in between used vigorously to promote international scientific exchanges. Elis Strömgren (1870 – 1947) was professor of astronomy at Copenhagen University 1907 – 1949. His eldest son and successor Bengt Strömgren (1908 – 1987) co-founded the new discipline of astrophysics in a long, fruitful, and highly distinguished career in both Denmark and the USA. Already in 1908, the Carlsberg Foundation awarded its first major grant to the Danish astronomer and historian of science, Johan Dreyer. He had a 20-year astronomical career behind him in Ireland, i.a. publishing a “New General Catalogue of Clusters and Nebulae” (NCG) and an “Index Catalogue” (IC) of further such objects, which are still in use today: The acronyms NGC and IC are familiar to any modern astronomer. In his retirement, he undertook the Herculean task of collecting, editing, and publishing the complete works of his illustrious predecessor. The fifteen large volumes – in the original Latin – appeared in print during the years 1921-1929 (the last one posthumously), a fitting monument to Tycho Brahe, Dreyer himself, and the Carlsberg Foundation. As a young man, Johan L.E. Dreyer (1852 – 1926) caught interest in astronomy. He later moved to Ireland to work, first with Lord Rosse, then at Dunsink, and finally as Director of Armagh Observatory until 1916, when he retired to Oxford. He was President of the Royal Astronomical Society 1923 – 1925. Cover page to Vol. I of Dreyer’s “Tychonis Brahe Dani Opera Omnia”. The Modern Era Begins: Bengt Strömgren Elis Strömgren’s eldest son Bengt was also born in 1908. As a prodigy, he published his first scientific paper at the age of 14 and passed schools and University with lightning speed. Naturally, as son of the professor and growing up at the Observatory, he had full command of all aspects of classical positional and dynamical astronomy. However, he was soon captured by the dynamic scientific atmosphere of Niels Bohr’s nearby Institute of Theoretical Physics (now the Niels Bohr Institute), where the new disciplines of atomic and nuclear physics, quantum mechanics, and relativity theory developed by leaps and bounds. From this “new physics”, he developed a deep understanding of the structure, chemical composition, energy sources, and ultimately the evolution of stars and galaxies – the branch of physics we now call astrophysics, synonymous with astronomy. As a leading figure in the international development of the physical basis for our present view of the universe, Bengt Strömgren was invited to work at several prestigious institutes in the USA and elsewhere in the 1930s. This resulted in groundbreaking papers on the structure of stars and the interstellar matter. In typical logical and methodical fashion, he also developed practical methods to determine the distances, motions, chemical composition and ages for large samples of stars by observation, as accurately and efficiently as possible. The ultimate goal was to map out the solar neighbourhood and understand its formation and evolution. However, such observations could not be made through the city lights of Copenhagen at an observatory from 1861 and with a train tunnel underneath. A new observatory was needed, far from large cities, with good atmospheric conditions by Danish standards and equipped with a carefully planned suite of modern instruments. Bengt Strömgren devised new, objective methods to characterise potential observatory sites, and several were investigated until a hill near the village of Brorfelde, 60 km west of Copenhagen, was selected as the best location. The War and Post-war Years - and the New Observatory Nevertheless, this was wartime; money was scarce everywhere and the senior professor took no interest. Therefore, nothing happened until 1944, the 300th anniversary of the birth of Ole Rømer, when the Carlsberg Foundation turned the tables with a large grant to purchase a modern meridian circle. This was intended to be the principal instrument of the new observatory and was first invented by Ole Rømer himself to measure stellar positions and motions precisely. A further generous grant from the Carlsberg Foundation in 1946 – Tycho Brahe’s 400th anniversary – finally put an end to 50 years of endless discussions and procrastination by providing the seed funds to construct the main building of the new observatory. This set the bureaucratic wheels of Government and University in motion: Finally, the work could start. Bengt Strömgren was already a famous astronomer when he spent 1936-8 at the University of Chicago. He was offered the Directorship of Yerkes Observatory in 1951, left for the Institute for Advanced Study (Princeton) in 1957, and returned to Denmark, Copenhagen University, and the Carlsberg Mansion in 1967. At least, so it was thought; but the bureaucratic machinery moved at glacial speed, but the poor Danish astronomical and political climates persisted and prevented Bengt Strömgren from making the scientific impact of which he knew he was capable. So, despite the efforts of the Carlsberg Foundation and others to retain him, he left Denmark for the USA, first part-time, then permanently in 1958, just as the Brorfelde observatory to which he had dedicated the previous two decades, was completed. Bent Strömgren in the USA, ca. 1957. © Library of Congress. A New Professor and a Fresh Start Anders Reiz, with a record of front-line research in theory and instrumentation in Sweden, took over the Chair of Astronomy in 1958. A daunting task awaited him: Restoring the economy of the institute and completing the equipment of the new observatory with new telescopes. Fortunately, this was also the year of the “Sputnik shock”; funding for the natural sciences was rising steeply, and Reiz was a consummate fundraiser. He also wanted to broaden the scientific profile of the institute into relevant theoretical fields using the latest research tool – an electronic computer, which was also needed to reduce the observational data from the meridian circle and other telescopes at Brorfelde. Aerial view of Brorfelde Observatory in the mid-1980s. © Copenhagen University. Brorfelde Observatory was equipped for the observations needed to explore the history of the Milky Way: A meridian circle to measure positions and motions of stars; photometric telescopes to measure colours and ages, and a wide-field Schmidt telescope to obtain spectra and chemical compositions. Again, in 1962, the Carlsberg Foundation put Danish astronomy in a leading position by funding a GIER electronic computer (Institute of Geodetics Electronic Calculator – with all of 1k of memory!), the first modern computer at the University. It inaugurated a research activity in stellar evolution, which placed Denmark at the top of the field for the next 15 years. Equally importantly, Copenhagen astronomy students became proficient with computers as the new tool for science, long before students in other fields. The International Breakthrough The European Southern Observatory (ESO) was founded by six countries in 1962 to create a competitive facility for European astronomy, from 1964 located at La Silla in Chile. With now 16 member states, ESO is the pre-eminent organisation for ground-based astronomy in the world. In 1967, Denmark joined ESO and its observatory at La Silla in Chile through Anders Reiz’ vigorous efforts: Observational programmes were no longer hampered by national borders or the Danish climate. Through European cooperation, Danish astronomers also obtained access to larger and better telescopes than we could ever dream of in Denmark. Brorfelde’s 50 cm photometric telescope was promptly moved to La Silla and became vastly more productive than it had ever been in Denmark. Moreover, the Carlsberg Foundation again topped up the funds for a third main telescope at Brorfelde in order to build a modern 1.5m reflecting telescope at La Silla in partnership with ESO. Back then, ESO was just taking its first difficult steps to become a modern observatory; today it is the world’s premier astronomical research organisation. In summary, the ESO membership gave Danish astronomy an enormous boost, both in quantity and quality, and it taught us that we could and should compete with the best in the world. La Silla – European Southern Observatory’s (ESO’s) first observatory in Chile; the Danish 1.5m telescope is seen at right. © Y. Beletsky (LCO)/ESO. The 1.5-m telescope was funded by the Carlsberg Foundation and ESO. It was used for many Danish research projects: Discovery of the first supernova at a cosmic distance (birth of the accelerating universe); remote galaxies at redshift ~3; black holes in giant radio galaxies; velocities of 100,000 stars, etc. On the Danish entry into ESO, Bengt Strömgren was offered the Carlsberg residence of honour – the greatest token of esteem Denmark could then offer a living scientist – and a personal professorship. At the same time, air travel and other forms of communication had become much easier. In summary, he returned in 1967 to spend his last twenty years in Denmark, becoming, i.a., President of the ESO Council, of the International Astronomical Union, and of the Royal Danish Academy of Sciences and Letters. His inspiration and initiatives to undertake large, systematic research projects in Galactic astronomy survived for decades after his own death in 1987. Expanding to the Northern Hemisphere The Nordic Optical Telescope (NOT) at the observatory on La Palma. © NOTSA Around 1980, the Danish 1.5m telescope and ESO’s largest telescope (mirror diameter 3.6m) were both operational and kept most Danish astronomers busy. However, a group of Nordic astronomers, led by Professors Reiz and Strömgren, wanted to build a Nordic 2.5m telescope at the new Spanish observatory on La Palma in the Canary Islands. A grant from the Carlsberg Foundation supported a design study of the telescope and in 1984 led to an agreement between the Nordic Council of Ministers and the Nordic research councils to build this Nordic Optical Telescope (NOT). After a difficult initial period, the last 20 years have seen an unbroken series of major Danish and Nordic research achievements with the NOT – too many to describe here, but often supported by individual grants from the Carlsberg Foundation. The NOT, optimised for flexibility and rapid response, has yielded many notable Danish scientific successes, not only in the study of the mysterious gamma-ray bursts in tandem with the ESO VLT, but also on asteroseismology, extrasolar planets, star clusters, the origin, and chemistry of halo stars in the Milky Way, etc. It is noteworthy that the Carlsberg Foundation’s support to build the NOT came at the same time as another large grant to convert the meridian circle in Brorfelde to automatic operation and relocate it to La Palma in 1984. At the solemn dedication of the observatory in 1985, the instrument was therefore aptly renamed the “Carlsberg Automatic Meridian Circle (CAMC)”. After nearly 30 years of uninterrupted operation every clear night as the world’s first successful robotic telescope, it was finally decommissioned in 2013. The CAMC initially observed one star at a time (~500 per night) with a scanning micrometer; no operator was needed. From 1998, a fixed CCD detector allowed to track an entire strip of sky with ~100,000 much fainter stars all night, and the operation was made fully automatic. 15 large catalogues of accurate positions have been published. Partial view of the Observatorio del Roque de los Muchachos on La Palma. The Carlsberg Automatic Meridian Circle (CAMC) is installed in the low building at far left. New Institutional and Personal Challenges Unfortunately, the time for blissful research did not last long. In the spring of 1985, the Danish universities faced a sudden budget cut that forced them to dismiss ~10% of the scientific staff. As the elected Department Head, the author had to face the imminent loss of my two most indispensable colleagues – including the leader of our flagship project, the CAMC. My only short-term option was to apply for unpaid leave of absence myself, clearly a temporary solution. However, the Carlsberg Foundation granted us salary and travel support for two years in the USA (I am married to a fellow astronomer, with three children), and off we went. In the event, the years in the USA were most productive scientifically, and I also became involved in the development of the then-new charge-coupled device (CCD) detectors, eventually to much benefit for both Danish and Nordic astronomy. However, the background was grim indeed. Moreover, as these lines are being written, budgets seem poised for another, similar cycle… Meanwhile, a new crisis was waiting around the corner: In 1987, ESO decided to construct the “Very Large Telescope (VLT)” – four identical 8.2m telescopes that could be used individually or in combination as an equivalent 16m telescope. The VLT project implied a doubling of ESO’s budget, but all member states voted in favour – all except Denmark, with a budget share of order 1%. The obvious implication would have been that we had to leave ESO with disastrous consequences for the future of Danish astronomy – a crisis that had to be resolved at virtually any cost. At the same time, the NOT project suffered a number of technical, financial, and management setbacks that did not enhance the reputation of the community in the eyes of decision makers. It was obvious that a solution to the crisis would cost us much of our previous government support; yet, this was insufficient. Again, the Carlsberg Foundation saved the day with a 10 million DKK grant that caused the government to reverse its earlier decision, and we could begin to breathe again. The VLT was eventually completed as a tremendous success, and the Danish membership of ESO has never been questioned again: A lesson was learned that is not soon forgotten. Remarkably, this large Carlsberg Foundation donation coincided with a grant to design and build a new, powerful, and versatile instrument (the Danish Faint Object Spectrograph and Camera – DFOSC) for the 1.5m telescope at La Silla – an instrument that proved so successful that a dozen copies were later built for other observatories, including the NOT. The European Southern Observatory today: ESO’s “Very Large Telescope” (VLT) at Paranal observatory in northern Chile. © J.L. Dauvergne & G. Hüdepohl, ESO Rebuilding the Community’s Reputation The years after 1990 were lean, until the funding crisis was resolved and the structure, leadership, instrumentation, and finances of the NOT had been fully reorganised. As the NOT began to fill its intended role as the main observational facility for Nordic astronomy in the northern hemisphere, we – and not least myself – could begin to face our funders again. As a further encouragement in this dark period, another large grant from the Carlsberg Foundation funded a wide-field CCD camera for the NOT, which remains the most sensitive camera at the observatory. Since 1992, astronomy is integrated in the physics institutes in Copenhagen and Aarhus; the old observatories and later the Danish telescopes at ESO are closed; the scientific profile has changed totally; instrumentation is focused on ESO and NOT; and new staff has attracted external grants and large research groups. Meanwhile, a generation change in the scientific staff was taking place. Drastic institute restructuring and rationalisation was also implemented – not with everybody’s approval. In this process, the Brorfelde observatory closed at the end of 1995, after 50 years of operation. The loss of Brorfelde’s excellent working conditions and outstanding team spirit was painful to all staff, but science keeps marching on. With hindsight, the superior climatic conditions in Chile and the technical expertise at ESO rendered Brorfelde obsolete as a scientific facility from the day Denmark joined ESO. Fortunately, Brorfelde is now being resurrected as a facility for attracting eager young schoolchildren to the natural sciences and exposing them to the wonders of the dark sky: “Per aspera ad astra”! Structure and Evolution of the Milky Way – a ‘Leitmotiv’ Throughout the 20th Century The Milky Way Galaxy as it would appear to an outside observer – a spiral galaxy consisting of billions of stars. © NOTSA A century ago, it was recognised that the Milky Way Galaxy is a spiral galaxy among many others, composed of stars like the Sun and the Solar System far from its centre. Nevertheless, how did it form and acquire its present properties? It became a lifelong quest for Bengt Strömgren already from his teenage years to understand this process, based on state-of-the-art physics. He did pioneering work to clarify the structure, chemical composition, energy sources, evolution and ages of stars, the laws governing their motions, and the structure of the interstellar matter. He also developed practical methods to determine the key astrophysical parameters by observation, accurately and efficiently. In short, he was one of the very few scientists to fully understand all aspects of the subject from a half-century of own seminal theoretical and observational contributions. Artist’s impression of the distribution of our ~15,000 Milky Way stars near the Sun – in the centre, from where we observed these stars. © Lars Christensen/ESO. When Bengt Strömgren returned in 1967, he brought along all the scientific, technical, and organisational experience he had accumulated abroad. With the advent of easy air travel and Denmark’s fresh membership of ESO, including the 50 cm telescope from Brorfelde and the new 1.5m telescope at La Silla, he wasted no time in initiating a series of very ambitious all-sky observing programmes to map out the properties of the stars in the vicinity of the Sun. He had already developed and tested an optimum colour system to determine the ages and metal content of Solar-type stars; efficient instruments and computerised data acquisition systems for telescopes at both La Silla and in the USA were designed and built (in ~1970); they were used by Dr. E.H. Olsen to observe ~30,000 stars all over the sky. And the Brorfelde meridian circle was moved to La Palma as the “Carlsberg Automatic Meridian Circle”. Whenever a well-motivated need arose, the Carlsberg Foundation came to the rescue, circumventing bureaucratic obstacles as needed. The evolution of the Milky Way disk is traced by the ages, chemical composition and 3D orbits of nearby stars; Bengt Strömgren was central to all these subjects. The figure and animation show the ~15,000 stars with complete data from the Danish/Swiss 25-year research programme – a key basis for today’s models. This story has a very personal angle: Around 1970, I had learned the trade of astronomical spectroscopy and formed a scientific and private partnership with Dr. Birgitta Nordström, a postdoc at Geneva Observatory. At that time, Bengt Strömgren hinted – ever so discreetly – that the missing link in his grand scheme was the capability to determine the velocity component along the line of sight – the radial velocity, which is measured from the Doppler shift of lines in the stellar spectrum. The ESO and later Danish 1.5m telescopes on La Silla – the latter another key donation by the Carlsberg Foundation and equipped with an efficient instrument developed in Geneva – became our main tools for the next 25 years. Animation showing how our stars moved in their last orbit around the centre of the Milky Way (taking ~225 million years), until we happened to observe them near the Sun. © Johan Holmberg and Lars Christensen/ESO But the Carlsberg Foundation not only helped when budgets were cut in 1985; after Birgitta Nordström had spent many years in part-time and/or soft-money positions, the Foundation also – quite exceptionally – granted her two three-year, full-time Senior Fellowships to finish our comprehensive inventory of ~15,000 solar-type stars in the Solar neighbourhood. Only this tangible proof of confidence enabled us to complete the project and publish “The Geneva-Copenhagen Survey of the Solar Neighbourhood” in 2004, with Birgitta Nordström as lead author along with several colleagues. The paper essentially embodies the realisation of Bengt Strömgren’s long-held vision and has subsequently been cited over 1,000 times. To conclude this chapter in the history of Danish astronomy, we organised a large international symposium, “The Galaxy Disk in Cosmological Context” in Copenhagen in 2008, the centenary of Bengt Strömgren’s birth. Support from the Carlsberg Foundation and others enabled us to organise a very successful scientific meeting, which we hope he would have enjoyed. The social programme included an afternoon event in the former Residence of Honour at Carlsberg - his home for the last twenty years of his life. The Carlsberg Residence of Honour – Bengt Strömgren’s home 1967 – 1987. A New Take-off in the 21st Century The last of the four ESO VLT telescopes was inaugurated in 2000, but the instrumentation plan dated from 1989. Scientific objectives and instrument technologies had changed drastically during that period, and a new generation of scientists with international experience and modern interests had entered Danish astronomy. ESO itself has entered the new field of (sub-)mm radio astronomy by becoming the European partner in the global short-wave radio observatory “Atacama Large Millimeter/submillimeter Array” (ALMA). ALMA is now in operation in Chile at 5,000m altitude, and new Danish staff with much international experience will ensure the future Danish competitive scientific returns from it in fields ranging from galaxies being assembled in the distant universe to planetary systems forming in our own back yard. The Atacama Large Millimetre/submillimetre Array (ALMA) observatory at 5,000m in the Atacama desert in northern Chile. © ESO Among the most prominent Danish research topics after 2000 are gamma-ray bursts and their host galaxies at huge distances; supernovae as probes of the accelerating expansion of the universe; the early stages of galaxies during the first few billion years after the Big Bang and the exploding field of exoplanets – planetary systems around other stars. New instruments were needed for these studies. Gamma-ray bursts present an extreme challenge, as they last for seconds to a few hours only, and may appear instantly anywhere in the sky. Observational clues to their nature are obtained from spectra, taken as early as at all possible and covering the entire wavelength range from ultraviolet to near-infrared. A new Danish instrument design, “X-shooter”, therefore allowed to split the light into three simultaneous, optimised channels; it was built partly at the Niels Bohr Institute, thanks to another grant from the Carlsberg Foundation. Artist’s impression of the fireball and relativistic jet emitted when a star in a remote galaxy explodes as a gamma-ray burst. © Bill Saxton, NRAO/AUI/NSF. X-shooter was installed at the VLT in 2009 as the instrument in highest demand of any at ESO and has produced many important scientific results. Building on this success, a new instrument, the “NOT Transient Explorer (NTE)”, patterned after the X-shooter, but fitting the 2.5m NOT and with added imaging capability, is now being built – again funded by a large grant from the Carlsberg Foundation. The NTE will then become the only instrument at the main focus of the NOT– always ready for instant action – making the telescope the most powerful facility in the world in this very competitive field. Exoplanets – planetary systems around other stars – were discovered in 1995 and are another booming field in astronomy. Danish researchers are prominent in both theory and observations of exoplanets, and the Carlsberg Foundation is funding a new instrument to make the NOT excel also in this subject. Once again, the Carlsberg Foundation is thus putting Danish astronomy right in the front. The challenge is to maintain that position as ESO’s new mega-project, the 39m E-ELT, goes into operation in ~2025 together with new space missions, planned and launched by the European Space Agency (ESA) in concert with ESO. Artist’s impression of the 39m European Extremely Large Telescope (E-ELT), recently approved for construction at Cerro Armazones in Chile, close to the VLT on Paranal. © ESO. Epilogue Telescopes and instruments are merely tools; but good tools and promising opportunities also attract brilliant people with innovative ideas. During the last decade alone, Danish astronomy could boast three large centres funded by the Danish National Research Foundation, and the annual Danish astronomy meetings now gather nearly 100 scientists of all ages. Moreover, the entire staff of these centres is fully international, ensuring the permanent contact to front-line global astronomy and a fruitful two-way flux of bright young people. Even more remarkably, female scientists have become a normal feature in the institutes, thanks to a deliberate policy of hiring only the best – consistent with the policy of the Carlsberg Foundation, which has secured the services of several good researchers with non-standard backgrounds for Danish astronomy. With 50 years of hindsight, the most impressive characteristic of the Carlsberg Foundation is not the volume of individual grants, but the consistent vision for the future of Danish astronomy and the will to take bold, forward-looking initiatives, even when success is not guaranteed and events may follow a different course than foreseen. At the same time, the Foundation has had the foresight to invest in the best of the new generation of scientists. As this writer has seen time and again, the Carlsberg Foundation’s unique reputation for scientific judgement and integrity has often led other actors – including the Government – to take decisions with positive effects reaching decades into the future. Such confidence is an inspiring obligation for the community – the writer included – and all indications are that the groundwork laid providently by the Carlsberg Foundation will secure a vibrant future for Danish astronomy throughout the first half of the 21st century.