‘The grand strategy of an observatory’: George Airy's vision for the division of astronomical labour among observatories during the nineteenth century

The downfall of the Parramatta Observatory during the 1840s led the British Government to reconsider the funding it provided to observatories. George Biddell Airy—the Astronomer Royal at the Royal Observatory, Greenwich—recommended the establishment of a central Colonial Board of Visitors (based in London) to oversee the management of observatories within the British Empire. The recommendation ultimately never materialized, but it showcased the support of the astronomical community and the British Government for centralizing the management of the vast network of observatories. This centralized vision continued to influence the founding of new observatories and the organization of their work. The article examines Airy's vision of a centralized organization of division of labour among observatories through his involvement in the discussions about the Colonial Board of Visitors. It also examines how he continued supporting the same vision through articles about the work of observatories, and through written advice about establishing observatories. The article demonstrates how he envisioned the grand strategy of an observatory to encompass public utility while also fitting it within the general policy of observatories in relation to the division of astronomical labour.

THE ROA LASER STATION: FROM ARTIFICIAL SATELLITES TO SPACE DEBRIS TRACKING

The Royal Observatory of the Spanish Navy (ROA) is specialist in space geodesy since the beginning of the space race. In 1975 a laser station was installed at ROA in collaboration with the French CERGA (Centre de Recherches en Géodynamique et Astrométrie). Since 1980, ROA has operated that station by their own. This equipment routinely tracks artificial satellites equipped with retro-reflectors. In 2014 ROA opened a new field of research: tracking of artificial satellites currently not active and equipped with retroreflectors. This new area was a challenge given the poor orbital accuracies that are available for these objects as they were not tracked on a routine basis. This served as an approach to our final goal: to strictly monitor space debris, this is, any type of uncontrolled man-made orbiting objects. To fulfill the objective, since 2017, we made significant changes to our laser installation. The most important was the replacement of the old laser bench with two new ones. One transmitting 500 mW-pulses, and another laser bench with 25 W transmission power. The study for the installation of the later laser was financed through European Union (EU) H2020 fundings and granted by the Spanish Centre for Industrial Technological Development (CDTI). Although it allows the tracking of collaborative objects, it is ideal for tracking non-collaborative too. Tracking activities begin in November 2017. From then onward, non-collaborative objects are monitored on a regular basis. This work shows the modifications already made, and the results obtained until 2019.

Juventas Cubesat for the Hera mision

<p>The Juventas CubeSat, will be delivered to the Didymos binary asteroid system by ESA's Hera mission within the context of the Asteroid Impact and Deflection Assessment (AIDA) international collaboration. AIDA is a technology demonstration of the kinetic impactor concept to deflect a small asteroid and to characterize its physical properties. Due to launch in 2024, Hera would travel to the binary asteroid system Didymos. It will explore the binary asteroid and the crater formed by the kinetic impact the NASA’s Double Asteroid Redirection Test (DART). HERA will carry two 6U CubeSats, one of which is the Juventas CubeSat developed by GomSpace Luxembourg with the Royal Observatory of Belgium as principal investigator. The spacecraft will attempt to characterize the internal structure of Didymos’ secondary body, Dimorphos, over a period of roughly 2 months using a low-frequency radar, JuRa. During this period, Juventas will also perform radio science measurements using its Inter-Satellite-Link to characterize the mass and mass distribution of Dimorphos. Afterwards, Juventas will attempt to land on Dimorphos, during which the spacecraft is expected to perform several bounces. Once landed, Juventas will use its gravimeter GRASS to obtain measurements of the surface acceleration on Dimorphos for a nominal duration of two orbits. Through the monitoring of dynamics for landing and bouncing impacts as well as measurements from the GRASS gravimeter payload while on the surface, Juventas will determine surface mechanical properties and provide further information on subsurface structure and dynamical properties of Dimorphos.</p>

The spring of order: Robert Main’s management of astronomical labor at the Royal Observatory, Greenwich

During the early nineteenth century the Royal Observatory, Greenwich, significantly increased the number of individuals it employed. One of the new roles created was the position of First Assistant, who oversaw the management of astronomical labor at the observatory. This article examines the contribution of Robert Main, who was the first person employed in this role. It shows that, through Robert Main’s duties and tasks, the observatory appears as a hybrid site embodying aspects of the other institutions that formed part of its operational network. Moreover, it demonstrates that the transformation of the observatory during the nineteenth century was driven by his rigorous maintenance of discipline in relation to the daily operations of the site.

Managing the observatory: discipline, order and disorder at Greenwich, 1835–1933

This article presents a case study of life and work at the Royal Observatory at Greenwich (1835–1933) which reveals tensions between the lived reality of the observatory as a social space, and the attempts to create order, maintain discipline and project an image of authority in order to ensure the observatory's long-term stability. Domestic, social and scientific activities all intermingled within the observatory walls in ways which were occasionally disorderly. But life at Greenwich was carefully managed to stave off such disorder and to maintain an appearance of respectability which was essential to the observatory's reputation and output. The article focuses on three areas of management: (1) the observatory's outer boundaries, demonstrating how Greenwich navigated both human and environmental intrusions from the wider world; (2) the house, examining how Greenwich's domestic spaces provided stability, while also complicating observatory life via the management of domestic servants; and (3) the scientific spaces, with an emphasis on the work and play of the observatory's boy computers. Together, these three parts demonstrate that the stability of the observatory was insecure, despite being perpetuated via powerful physical and social boundaries. It had to be continually maintained, and was regularly challenged by Greenwich's occupants and neighbours.

M3G: an expanding catalogue of permanently tracking GNSS stations in Europe

<p>The Metadata Management and Distribution System for Multiple GNSS Networks (M<sup>3</sup>G, https://gnss-metadata.eu), hosted by the Royal Observatory of Belgium, is one of the services of the European Plate Observing System (EPOS, https://www.epos-eu.org) and EUREF (http://euref.eu).</p><p>M<sup>3</sup>G provides the scientific as well as the non-scientific community with a state-of-the-art archive of information on permanently tracking GNSS stations in Europe, including the station description, the GNSS networks the stations contribute to, whether station observation data are publicly available, and how to access them. </p><p>Since its first public release (2018), M<sup>3</sup>G has been under continuous development, to respond to the evolving needs of the GNSS community, to progress towards FAIR data principles and comply with GDPR. </p><p>M<sup>3</sup>G offers APIs and an interactive user interface where any GNSS station manager, after registration, can insert all information relative to its GNSS stations and make this information publicly available. Consequently, the commitment of station managers to insert GNSS station metadata in M<sup>3</sup>G and their willingness to keep the information up to date is crucial for the success of M<sup>3</sup>G.</p><p>At the moment, M<sup>3</sup>G is used by 127 GNSS agencies and includes data from more than 2500 GNSS stations all over Europe, and more still in the process of being collected.</p><p>We will illustrate the rationale underlying M<sup>3</sup>G, the data that it provides and how these data can be accessed.</p>

The cause of the appearance or disappearance of the Rieger-type periodicity in the northern and southern hemispheres of the sun

We use a continuous wavelet transform to analyse the daily hemispheric sunspot area data from the Greenwich Royal Observatory during cycles 12–24 and then study the cause of the appearance or disappearance of the Rieger-type periodicity in the northern and southern hemispheres during a certain cycle. The Rieger-type periodicity in the northern and southern hemispheres should be developed independently in the two hemispheres. This periodicity in the northern hemisphere is generally anti-correlated with the long-term variations in the mean solar cycle strength of hemispheric activity, but the correlation of the two parameters in the southern hemisphere shows a weak correlation. The appearance or disappearance of Rieger-type periodicity in the northern and southern hemispheres during a certain solar cycle is not directly correlated with their corresponding hemispheric mean activity strength but should be related to the strength of the hemispheric activity during sunspot maximum times, which hints the Rieger-type periodicity is more related to temporal evolution of toroidal magnetic field. The Rieger-type periodicity in the two hemispheres disappears in those solar cycles with relatively weak hemispheric activity during sunspot maximum times. The reason for the disappearance of this periodicity may be due to the combined influence of relatively weak toroidal magnetic fields and torsional oscillations, the differential rotation parameters vary through the solar cycle and may not remain more or less unchanged during some time, which does not permit the strong growth of magnetic Rossby waves.