Session Chair: Edward Gillin (University College London, UK)
Chaîne opératoire : outil méthodologique d’étude du fonctionnement d’une institution scientifique
Auteur: Julien Gressot
L’étude du fonctionnement des institutions scientifiques s’est développée ces dernières années avec en particulier le croisement de l’analyse des sources manuscrites avec celle de la culture matérielle. Le concept de chaîne opératoire est une proposition méthodologique favorisant l’étude d’une institution scientifique dans sa globalité incluant les opérations techniques, matérielles, pratiques ou encore cognitives permettant, en bout de chaîne, d’obtenir des données précises. Il permet d’attirer l’attention sur l’intérêt d’étudier les instruments scientifiques en tant qu’ensemble opératoire permettant d’obtenir une donnée précise plutôt qu’en tant qu’entité isolée.
Utile pour comprendre les modalités de faire science, le concept attire également l’attention sur des opérations ou des instruments scientifiques généralement moins considérés car semblant d’une importance moindre. Ainsi cette proposition méthodologique entend faciliter à la fois la compréhension des phénomènes historiques mais permet aussi aux conservateurs-restaurateurs et aux muséologues un outil de médiation. Pouvant servir comme moyen heuristique ainsi que de synthèse permettant la comparaison entre différentes institutions ou différentes époques au sein d’un établissement, cette présentation entend aborder les apports et les limites du concept de chaîne opératoire en s’appuyant sur le cas de l’Observatoire cantonal de Neuchâtel.
Après une exploration de l’origines du concept, notamment par l’ethnologue préhistorien André Leroi-Gourhan et de son passage de l’archéologie à l’histoire des sciences, l’utilisation du concept sera exemplifiée à partir de l’Observatoire cantonal de Neuchâtel.
The Many Links in a Chain: Operating the Stockholm Observatory’s Ertel Meridian Circle, 1834-1931
Author: Johan Kärnfelt
In the 1820s, the Stockholm Observatory significantly upgraded its instrumentation. Among the new additions was a meridian circle, crafted by Traugott Ertel in Munich, which after considerable delay was installed at the observatory in 1834. This instrument featured a doublet lens manufactured by Merz, boasting an aperture of 11,4 cm and a focal length of 170 cm. Despite its capabilities, the instrument remained underutilized for the first forty years of its existence. This was largely due to the disinterest of the Observatory directors during that period, who did their main work in geodesy rather than in positional astronomy.
The instrument only realized its full potential when Hugo Gyldén assumed the role of Academy astronomer in 1871, effectively concluding the preceding geodetic era. Under Gyldén’s leadership, an ambitious zone project aiming at measuring the proper motions of 2000 northerly stars was conceived. The project would engage the observatory astronomers for over fifty years. The meridian circle eventually saw retirement when the Observatory relocated to a new, state-of-the-art facility in Saltsjöbaden in 1931. However, it found a new purpose as a training instrument and remained in use for many years to come.
In this paper, I will focus on the instrument's trajectory until its relocation to Saltsjöbaden, highlighting the many links that formed its chain of operation. Starting with technical links such as clocks and recording devices, I will move on to the human resources involved, including assistants and computers. Subsequently, I will delve into the scientific links, such as necessary star catalogues, before concluding with an examination of how the instrument was linked to society at large, particularly in the realms of geodetics and time signalling.
Creating Observatory Time at Dartmouth College in the 1860-70s.
Author: Richard Kremer
Part of the “observatory movement” in the United States, Dartmouth College’s Shattuck Observatory opened in 1853 with a 6.4-inch refractor by Merz & Mahler of Munich, a 4-inch transit telescope by Troughton & Simms of London, and an astronomical regulator by Utzschneider and Fraunhofer, also of Munich. But with only human (rather than mechanical) links between the clock and the transit telescope, the new observatory could correlate clock and sky time only to a precision of about a second. In this paper, I will examine how Charles A. Young, appointed professor of natural philosophy of astronomy at Dartmouth in 1866, sought to create observatory time by linking a seconds-beating clock electromagnetically to what he called a “printing chronograph” and to the finger of the astronomer “observing” transits. Surviving archival materials provide detailed views into Young’s efforts to build a reliable “operating chain” (Gressot) of pendula, clockworks, electromagnetic coils, mechanical governors, human sensory systems, observatory couches, and seeing conditions. Yet by 1877, when he departed Dartmouth for Princeton, Young had not reached his goal of timing celestial motions to hundredths of a second.
Time Services and Observatories: A Study Case of the Brazilian National Observatory.
Author: Sabina Luz
The time services at observatories were a daily activity that had to be continued for the purpose of keeping the time and, also, its precision. The instruments and methods employed were similar even in different contexts, countries, and cultures. However, the particularities of each observatory and its political, social, and cultural differences are important elements to be considered at the analyses of the scientific practices at time services in observatories. In this paper I will examine the time service at the National Observatory of Brazil at the first decade of 20th century. The time service was one of the main activities of this institution and it was connected to time transmission to Rio de Janeiro’s harbor. This service was provided by an active participation of mariners since the 19th century. The main instruments used for time calculation were a transit telescope by Dollond (256 x 169 x 97 cm) with 7 cm aperture, acquired in 1851 by the Observatory and used until 1920; a pendulum clock number 101 by Auguste Fénon, acquired probably in 1889; and several chronometers from different instrument makers, but all European. The instruments, the practices and the workers at the observatory will be analyzed in order to understand how an operating chain was established at this institution. Finally, the quest for precision at the astronomical time measurements and time keeping at this observatory will also be investigated not only as an element of the scientific practice but also as an aspect of advertising and scientific authority.
