Human habitats: prospects for infrastructure supporting astronomy from the Moon.

There is strong interest in lunar exploration from governmental space agencies, private companies and the public. NASA is about to send humans to the lunar surface again within the next few years, and ESA has proposed the concept of the Moon Village, with the goal of a sustainable human presence and activity on the lunar surface. Although construction of the infrastructure for this permanent human settlement is envisaged for the end of this decade by many, there is no definite mission plan yet. While this may be unsatisfactory for the impatient, this fact actually carries great potential: this is the optimal time to develop a forward-looking science input and influence mission planning. Based on data from recent missions (SMART-1, Kaguya, Chang'E, Chandrayaan-1 and LRO) as well as simulation campaigns (e.g. ILEWG EuroMoonMars), we provide initial input on how astronomy could be incorporated into a future Moon Village, and how the presence of humans (and robots) on the Moon could help deploy and maintain astronomical hardware. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades'.

LOUPE: observing Earth from the Moon to prepare for detecting life on Earth-like exoplanets.

LOUPE, the Lunar Observatory for Unresolved Polarimetry of the Earth, is a small, robust spectro-polarimeter for observing the Earth as an exoplanet. Detecting Earth-like planets in stellar habitable zones is one of the key challenges of modern exoplanetary science. Characterizing such planets and searching for traces of life requires the direct detection of their signals. LOUPE provides unique spectral flux and polarization data of sunlight reflected by Earth, the only planet known to harbour life. These data will be used to test numerical codes to predict signals of Earth-like exoplanets, to test algorithms that retrieve planet properties, and to fine-tune the design and observational strategies of future space observatories. From the Moon, LOUPE will continuously see the entire Earth, enabling it to monitor the signal changes due to the planet's daily rotation, weather patterns and seasons, across all phase angles. Here, we present both the science case and the technology behind LOUPE's instrumental and mission design. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades'.

"Todos los instrumentos están en buen estado". Disputas en torno al funcionamiento de los telescopios del Observatorio Astronómico Nacional de Chile en el siglo XIX / All instruments are in good condition". Disputes surrounding the operation of the telescopes at the National Astronomical Observatory of Chile in the 19th Century

El artículo analiza una controversia pública sobre el estado de los principales instrumentos del Observatorio Astronómico Nacional de Chile a fines del siglo XIX, las labores de reparación y mantención de estos y la producción científica de la institución. En la controversia participaron una amplia gama de actores, entre los que se encuentran miembros del Congreso Nacional, ministros de Estado, astrónomos, mecánicos y arquitectos. Este caso permite examinar la estrecha vinculación entre la esfera política y la tecnocientífica, evidenciándose en la administración, financiamiento, evaluación y fiscalización del quehacer del observatorio astronómico. Acá podemos observar cómo el cuestionamiento sobre la calidad científica, como el estado de los instrumentos de la institución, enfrentó no solo los juicios, sino la autoridad de quienes los emitían. Por otro lado, esta controversia permite observar cómo la necesidad de crear tecnologías asociadas y adaptar los instrumentos astronómicos dio un protagonismo a mecánicos, ingenieros y arquitectos, actores muchas veces invisibles en comparación con los astrónomos

This paper analyses a public controversy about the state of the main instruments at the National Astronomical Observatory of Chile at the end of the 19th century, the repair and the maintenance work of these tools and the scientific production of this institution. The controversy involved a wide range of actors, including members of the National Congress, ministers of State, astronomers, mechanics and architects. This case examines the close link between the political and the techno-scientific spheres, evidenced in the administration, financing, evaluation and oversight of the work of the observatory. We can observe how the questioning of scientific quality, such as the state of the instruments of the institution, faced not only the judgments, but also the authority of those who issued. Also, this controversy allows us to observe how the need to create associated technologies and adapt astronomical instruments gave prominence to mechanics, engineers and architects, actors often invisible in comparison to astronomers

Improved X-ray computed tomography reconstruction of the largest fragment of the Antikythera Mechanism, an ancient Greek astronomical calculator.

The Antikythera Mechanism is an extraordinarily complex ancient Greek astronomical calculating device whose mode of operation is now relatively well understood particularly since imaging studies in 2005 revealed gears and inscriptions which were previously illegible. Unfortunately, the highest resolution X-ray computed tomography image of the largest fragment had some errors which meant that the reconstructed images were not as clear as had been expected. Here, the original X-ray data have been reanalysed and reconstructed. The new X-ray computed tomography images have improved contrast and resolution, leading to better clarity and legibility. The improvement in image quality is characterised and some examples of writing on the Mechanism which can now be read with increased confidence are given.

A broadband chip-scale optical frequency synthesizer at 2.7 × 10(-16) relative uncertainty.

Optical frequency combs-coherent light sources that connect optical frequencies with microwave oscillations-have become the enabling tool for precision spectroscopy, optical clockwork, and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but Kerr nonlinear dynamics in high-Q solid-state microresonators has recently demonstrated promising features as alternative platforms. The advance not only fosters studies of chip-scale frequency metrology but also extends the realm of optical frequency combs. We report the full stabilization of chip-scale optical frequency combs. The microcomb's two degrees of freedom, one of the comb lines and the native 18-GHz comb spacing, are simultaneously phase-locked to known optical and microwave references. Active comb spacing stabilization improves long-term stability by six orders of magnitude, reaching a record instrument-limited residual instability of [Formula: see text]. Comparing 46 nitride frequency comb lines with a fiber laser frequency comb, we demonstrate the unprecedented microcomb tooth-to-tooth relative frequency uncertainty down to 50 mHz and 2.7 × 10(-16), heralding novel solid-state applications in precision spectroscopy, coherent communications, and astronomical spectrography.

Reading Cosmographia: Peter Apian's Book- Instrument Hybrid and the Rise of the Mathematical Amateur in the Sixteenth Century.

The incorporation of paper instruments, also known as volvelles, into astronomical and cosmographical texts is a well-known facet of sixteenth-century printing. However, the impact that these instruments had on the reading public has yet to be determined. This paper argues that the inclusion of paper instruments in Peter Apian's Cosmographia transforms the text into a book-instrument hybrid. The instruments and accompanying text in Cosmographia enabled readers to make their own measurements and calculations of both the heavens and the earth. Through the experience of manipulating the instruments, the readers became participants in sixteenth century mathematical culture, and thus mathematical amateurs. I conclude that the presence of these mathematical amateurs contributed to a much broader social base for the cultural shift towards an empirical understanding of nature from 1500 to 1700.

"Perhaps Irrelevant". The Iconography of Tycho Brahe's Small Gilt Brass Quadrant.

When Tycho Brahe published a description of his astronomical instruments in 1598 as part of a strategy to procure royal patronage, it was not with one of his grander, precision measurement tools that he opened his account, but rather a small brass quadrant with limited observational utility. The defining feature of this instrument was seemingly a small emblematic image inscribed within the arc of the quadrant. Through this symbolic motif Tycho conveyed a moralising message about the relative worth of astronomy. Considering a range of visual productions that may have influenced his iconography, the present paper situates the quadrant within the broader context of Renaissance visual culture and examines the significance of the quadrant in Tycho's wider instrument collection.

Moving Shadows, Moving Sun. Early Modem Sundials Restaging Miracles.

Irrespective of geo- or heliocentric presuppositions, the functioning of sundials is based on the observation of moving shadows or light spots. Even though the cast shadow was often simply used to indicate the time, it could also remind the users of the ephemerality of earthly things or function as an index of planetary movements. This article examines the various ways in which early modem sundials visually interpret the moving shadow or light spot. The instruments address the shadow in inscriptions, integrate it into their design (e.g., in cruciform dials) or even manipulate its course (as in the so-called Horologium Ahaz). Both the crucifix and the Ahaz dials not only refer to astronomical miracles but actually restage them. Even though by means of the horologium it was not possible to explain the Old Testament miracle of the shadow moving backward, adepts were able to recreate it on a terrestrial scale.

Perfect in Every Sense. Scientific Iconography on an Equation Clock by Jost Bürgi and the Self-Understanding of the Astronomers at the Kassel Court in the Late 1580s.

At the center of this article is an iconographic analysis of the eight silver reliefs on the sides of a table clock made in 1591 by Jost Burgi, the court clockmaker of Landgrave Wilhelm iv of Hessen-Kassel. The reliefs present an astronomical ancestral picture gallery, running from the Patriarchs of the Old Testament to Copernicus. The author argues that the "storyboard" for this sequence of images must have been conceived down to its smallest details by the Kassel court astronomer Christoph Rothmann; indeed, many of the scenes shown, along with many particular details depicted within them, are literally described in Rothmann's never-published manuscript Observationes stellarum fixarum of 1589. The final section of the essay compares these reliefs to the images created for Tycho Brahe at his Uraniborg and Stjerneborg observatories. The author concludes that the sequence of the reliefs in Kassel, culminating in the representation of Copernicus and his world view, is a reflection of the acrimonious debate extending over many years between the heliocentrist Rothmann and the geo-heliocentrist Brahe regarding the veracity of the heliocentric world view.

Heavenly Networks. Celestial Maps and Globes in Circulation between Artisans, Mathematicians, and Noblemen in Renaissance Europe.

The aim of this paper is to examine the iconography on a set of star charts by Albrecht Dürer (1515), and celestial globes by Caspar Vopel (1536) and Christoph Schissler (1575). The iconography on these instruments is conditioned by strong traditions which include not only the imagery on globes and planispheres (star charts), but also ancient literature about the constellations. Where this iconography departs from those traditions, the change had to do with humanism in the sixteenth century. This "humanistic" dimension is interwoven with other concerns that involve both "social" and "technical" motivations. The interplay of these three dimensions illustrates how the iconography on celestial charts and globes expresses some features of the shared knowledge and shared culture between artisans, mathematicians, and nobles in Renaissance Europe.

Metrics of Justice. A Sundial's Nomological Figuration.

This paper examines a polyhedral dial from the British Museum made by the instrument maker Ulrich Schniep, and discusses the status of multifunctional scientific instruments. It discerns a multifaceted iconic meaning considering different dimensions such as scientific functionality (astronomy), the complex allegorical figure of Justice (iconography), and the representation of the sovereign (politics), the court and the Kunstkammer of Albrecht v of Bavaria. As a numen mixtum the figure of "Justicia" touches different fields that go far beyond pure astronomical measurement and represents the power of the ruler as well as the rules of economic justice.

The Palermo Merz Equatorial Telescope. An Instrument, a Manuscript, Some Drawings.

A manuscript by Georg and Sigmund Merz dated 1862 and containing instructions for assembling the equatorial telescope acquired by the Palermo Observatory is conserved in the archives of the Museo Astronomico e Copernicano in Rome. It is a rare document that reveals "tricks of the trade" and technical knowledge not usually included in textbooks or treatises. It was sent to the Palermo Observatory as an aid to the installation of the telescope, which made a signal contribution to the development of solar physics in Italy in the 19th century. Based on the study of unpublished sources (consisting of texts and drawings), the history of the instrument has been retraced. This paper presents a detailed description of the Merz manuscript (including a complete transcript) and some technical drawings recently discovered in the archives of the Palermo Observatory.

[The delayed emergence of the printing chronograph in French observatories (late 19th - early 20th centuries]. / L'émergence contrariée du chronographe imprimant dans les observatoires français (fin 19e--début 20e s.).

Western observatories became scientific factories from the mid-19th century. Astrometry symbolized the transition to an industrious economy of scientific practices. The printing chronograph, which reduced the personal equations of the observers, was, first in the United States, then in England, the symbolic instrument of this transformation. In France, the initiatives of the astronomer Liais were prototypical. In the practices of the Hendaye Observatory, and thanks to the abbé Verschaffel, the printing chronograph made its definitive entry in French observatories at the beginning of the 20th century. Excessive centralization of French astronomy, the authoritarianism of Urbain Le Verrier, the director of the Paris Observatory, and the poor market for scientific instruments explain why the printing chronograph took root, belatedly, in France.

Time, Weather and Empires: The Campos Rodrigues Observatory in Lourenço Marques, Mozambique (1905-1930).

In 1905 the Campos Rodrigues Observatory (CRO) was founded in Lourenço Marques (nowadays Maputo), the capital of Mozambique, by then part of the Portuguese overseas empire. In this paper the inception and early history of the CRO are analysed in the broader context of the interwoven history of the Portuguese and British empires in Africa, and specifically with respect to the scientific relations between Mozambique and South Africa. The equipment, personnel, practices and networks involved in the inception and early development of the CRO are brought into focus in order to illustrate the problems and strategies that shaped the establishment and functioning of this observatory, which was conceived essentially as a symbol of imperial stamina and colonial prowess. It is suggested that by providing a focal point for the development of scientific relations between Mozambique and South Africa, the CRO served both Portuguese ambitions for recognition as an imperial power and the emergence of South African nationalism.