1In 2013, Smithsonian Magazine published a special issue in attempt to define the United States of America in 101 objects (Caruso, 2013). The list included artifacts representing some of the greatest accomplishments and discoveries in American history, from Neil Armstrong’s spacesuit that he wore when he first stepped foot on the moon, to a gold nugget uncovered during California’s Gold Rush, and a vial that once contained Jonas Salk’s polio vaccine. One object listed, a three-and-a-half foot tall instrument enclosed in a case of metal, a fair example of what historians of technology would appropriately call a ‘black box,’ was used by an astronomer to revolutionize our understanding of the composition of the universe (e.g. Smith & Tatarewicz, 1994).

2Carnegie Institution of Washington physicist Kent Ford designed and built this instrument—an image tube spectrograph—in the late 1960s while collaborating with his colleague, astronomer Vera Rubin. For two decades, the pair travelled to several observatories in North and South America, attached their new observing aid to telescopes, and recorded the internal motions of several dozen spiral galaxies, ones much like our own Milky Way. Rubin discovered that the outer arms of each galaxy are rotating at speeds that should not have been possible given the amount of visible mass, primarily in the form of stars and dust. Rubin presented her work to the astronomical community and argued that a possible explanation was that some unknown material, that did not shine or reflect light the way stars or dust do, was present in the galaxy. This study provided the strongest observational evidence yet found for the existence of dark matter, a non-luminous material that was detectable by the gravitational forces it exerted on the material around it. By the 1980s, astronomers largely believed dark matter to comprise 90% of the total mass in the universe (Rubin, 1997, p. 129).

3Vera Rubin was able to find evidence of dark matter in part because of the research project she pursued and in part because of the instrument she employed. Rubin noticed that few other astronomers were interested in the rotational dynamics of galaxies, which attracted her to the problem (Rubin, 2007, p. 20). In the male-dominated field of astronomy, the recently-PhD astronomer chose a project with little competition, that she could develop on her own, and that she could tackle at her own pace. As Rubin was forming an interest in the outer bands of galaxies, she was hired at the Carnegie Institution of Washington’s Department of Terrestrial Magnetism, where Kent Ford was looking for a research program that would push his instrument to its limits (p. 21). With Ford’s instrument, using new photoelectronic technology to more efficiently observe very dim objects, Rubin could record the motion of fainter stars, with shorter exposure times, without the need for observing time on the largest telescopes. What began as an investigation to study the dynamics of spiral galaxies led to surprising results for both Rubin and the astronomical community at large. Though Rubin could not observe dark matter directly, by studying the motion of distant galaxies, she inferred that most galaxies must contain about ten times as much nonvisible as visible mass (Rubin, 1983, p. 96).

4While the benefits of using an image tube, an instrument that could amplify the light from a distant object, were apparent to much of the astronomical community, as seen in conference proceedings and correspondence with image tube developers, astronomers’ initial uptake of the device was limited. Though a few astronomers did attempt to use Ford’s instrument in the late 1960s and throughout the 1970s, with varying degrees of success in acquiring scientific data, the technology failed to gain widespread support.

5Several groups, primarily in the United States, England, France, and Russia, attempted to develop electronic cameras for astronomers. Some built instruments for specific observatories and astronomers, to be used for specific research projects. Others designed devices that could be used by any astronomer engaged in any research project. The Carnegie Image Tube Committee, or CITC, which operated from 1954 to 1976 was one of the most prolific producers of astronomical image tubes. The committee was created by Carnegie Institution president Vannevar Bush who, during World War II, led nearly all of the United States’ civilian-military research and development efforts from the U.S. Office of Scientific Research and Development (OSRD). After the war, Bush articulated and advocated for a highly influential vision for the relationship between science and government in the United States (Bush, 1945).

6Bush brought together a group of astronomers, physicists, and engineers. The project was coordinated through the Carnegie Institution of Washington’s Department of Terrestrial Magnetism. While singular in structure, this group collaborated and learned from members from observatories and laboratories across the United States, England, and France. The initial goal of the CITC was to “explore the possible use of electronic techniques, supplanting or supplementing present photographic methods, to increase the range of telescopes” (Carnegie Institution of Washington, 1953, p. 39). The Committee believed that an image tube would be useful in any astronomical observing program and should replace direct photography as the primary means of astronomical imaging. Additionally, the CITC hoped their exploration of devices and techniques would lead to the development of a “manufacturable device for general astronomical use at observatories everywhere” (Committee on Telescope Image Converters, 1958). At the beginning of their efforts, they envisioned a device with enough gain to be beneficial for astronomers engaged in any scientific research program, but whose operation was simple enough to be employed by any astronomer, regardless of training, at any observatory.

7During its first decade of operation, the CITC worked with industrial and military laboratories, private and public observatories, and individual astronomers to develop an image tube that they could market to the astronomical community. By 1964, after a ten-year period of research and development, the CITC decided they had developed an image tube that was ready for astronomical research, and though they wished to make further improvements to the device, they believed it was time to release the results of their efforts and receive the credit they believed they had earned from the astronomical community. Their tube did receive some modest use and helped astronomers acquire ground-breaking scientific results, including those of Rubin and Ford, but the technology was never fully adopted by the astronomical community.

8The CITC was not alone in its failure. The technology struggled to find any great uptake throughout the astronomical community and is largely forgotten today. At the Griffith Observatory in Los Angeles, an exhibit about the history of astronomical observations and advances in astronomical detectors leads the visitor from the eye, to photography, to CCDs. Not represented in this narrative, however, is the role of image tubes. This technology never fully replaced photography alone as the primary mode of imaging and both were supplanted by the introduction of charged coupled devices. To understand how this technology became a forgotten piece of astronomical technology history while also responsible for one of the greatest discoveries in twentieth century science, we can look at the CITC as an example. By examining the astronomy community’s response to the formation of the CITC, its development of the technology, and why astronomers did not adopt the final technology in significant numbers we can better understand how astronomers choose to integrate new technology into their work.

1.  The State of Astronomy

9During the first half of the twentieth century, telescope design appeared to approach a limiting size, restricted largely by funding and material constraints. In 1948, two decades after George Ellery Hale secured $6 million, the equivalent of roughly one and half billion U.S. dollars today (MacDonald, 2017, p.16) from the Rockefeller Foundation to construct a telescope on Mount Palomar in southern California, the telescope saw first light. Jointly operated by the Carnegie Institution of Washington and the California Institute of Technology, Hale’s telescope boasted a 200-inch-wide primary mirror that was lauded for its light-gathering power and resolution. Even as it was being constructed, however, astronomers questioned the usefulness of investing resources in such large-scale instruments.

10In his 1943 presidential address to the American Astronomical Society, astronomer Joel Stebbins, a pioneer in electronic detectors at the University of Wisconsin, raised the issue of the law of diminishing returns in the field of astronomy (Stebbins, 1944). Stebbins noted that a telescope twice the diameter may cost ten times as much to build, but the resulting gain in light-gathering power and resolution would not necessarily be proportional to the size or cost (p. 267-268). In 1956, Washburn Observatory astronomer and Stebbins protégé, A.E. Whitford, similarly argued that:

[…] the astronomical telescope has long since reached a state of perfection where the tranquility of the atmosphere, rather than the quality of the optics, determines the image quality. The astronomer may, in theory, gather more information by increasing the aperture, but the engineering difficulties and the cost both rise steeply for any considerable increase in size over that of existing telescopes. (Whitford, 1956, p. 25)

11Only a select group of astronomers would have access to a large telescope like Hale’s privately operated 200-inch, and few, if any, other astronomers or institutions could afford to devote the resources to constructing a rival instrument. The apparent size limit of optical telescopes restricted astronomers’ potential opportunity to see further and more distant.

12Some astronomers and physicists believed an alternative to constructing larger telescopes was to amplify the incoming light or increase the sensitivity of the telescope’s recording device. Whitford argued that:

The final link in the information chain, the radiation detector at the focus of the telescope, is therefore the element which must be scrutinized for possible lack of efficiency. If the efficiency is low, improvements can be counted as equivalent to increasing the aperture of existing telescopes. (ibid.)

13If offered the money for a 100-inch telescope, many astronomers, Stebbins asserted, would have the “moral courage” to say that they prefer to build an 80-inch telescope and use the remainder of the funds for improved instruments and better operations, arguing that, “if the law of diminishing returns seems to prevent us from doing something better, we can always try to do something different” (Stebbins, 1944, p. 271). Combining advanced instrumentation with modest-sized telescopes could have the effect of giving more astronomers access to adequate observing resources. Only small improvements in instrumentation were needed, Stebbins and Whitford concluded, to open new research opportunities for a wider field of astronomers.

14By the 1950s, there were several methods employed or proposed to electronically amplify the light coming from an object. Devices which used the photoelectric effect to convert photons into electrons that could be easily multiplied to produce a brighter image of the original object, were collectively called image tubes. Television tubes were a type of image tube and, like others, had advantages and disadvantages for astronomical work. Though television tubes had the potential to combine the technical advantages of photomultipliers with the spatial information provided by photography, they also had, for example, poor resolution and difficulty resolving scenes with small differences in contrast (Carnegie Institution of Washington, 1960, p. 293-306). In an effort to explore their possibilities, some astronomers experimented with electronic image tubes already successfully employed in commercially-available television cameras, which were not designed for the extremely low light levels required in astronomy. One group, for example, used commercially-available television tubes to conduct planetary studies (Somes-Charlton, 1958). Others, however, chose to develop instrumentation specifically for astronomical use. The image tube used by Vera Rubin and Kent Ford and developed by the Carnegie Image Tube Committee proved to be one of the most successful and persistent of the image tubes available for astronomers’ adoption before all image tubes were replaced by solid state devices in the 1980s.

15Of the numerous efforts to employ image tube technology to amplify and record two-dimensional signals, each had different resources, different design philosophies, and different audiences. The proposed devices also ranged widely in feasibility and usability. One example neatly illustrates the frustration some harbored over the problem. In 1950, Yerkes Observatory astronomer W. Albert Hiltner consulted with Radio Corporation of America (RCA) engineer George A. Morton about the possibility of developing an image tube to aid astronomical research (Livingston, 1973, p. 95). After considering the problem, Morton suggested that the quickest answer for astronomers was to purchase one-hundred photomultiplier tubes, which RCA also produced and sold, and situate them in an array to provide spatial data. This would have resulted in an unusually large detector and would have required extensive engineering work to calibrate the device into a uniform detector. This story demonstrates the perceived challenges that astronomers and industrial engineers alike saw in the development of image tubes for astronomical purposes and highlights the reaction astronomers faced when they inquired if commercial companies would support the development of astronomical instrumentation. Like many electro-optical companies, RCA wanted to expand their consumer base and sell more products, but they did not want to invest the resources required to design a device for the specific needs of every interested party.

16It was not until two decades after RCA brushed aside Hiltner’s request that several astronomers at the world’s largest observatories successfully applied image tubes in limited capacity. At Kitt Peak National Observatory in 1973, for example, astronomer William Livingston calculated that for the final quarter of 1972, 26% of the observing time on the Steward Observatory 225-cm telescope and 45% of the observing time on the Kitt Peak National Observatory 210-cm telescope were assigned for image tube-aided observations (p. 95). Because the Kitt Peak National Observatory was publicly funded, the large percentage of observing time dedicated to image-tube-aided observations supports the argument that astronomers without access to large telescopes at their home institutions valued access to electronic instruments on large telescopes. This was particularly important for astronomers interested in investigating new areas of research opened up or made easier with the equipment, like the study of the physical properties of distant, dim galaxies.

17During World War II, older astronomers were often hesitant about adopting the many new technologies that had arisen during both world wars, such as the photomultipliers developed by Stebbins and others. Most lacked the technical training to utilize newly discovered electronic techniques and were often reliant on those in industrial and military labs to aid in observations (DeVorkin, 1985). Astronomers had adopted photography and spectroscopy into their practice by the end of the nineteenth century. Younger physicists and astronomers who received training during military service were needed to move into the field of astronomy to direct advances in astronomical instrumentation.

2.  The Formation of the Carnegie Image Tube Committee

18At Mount Wilson, two physicists became important figures in determining the direction of development of image tubes at the Carnegie Institution. Ira Bowen, trained in physics under Nobel Prize winning physicist Robert Millikan at the California Institute of Technology (Caltech), used his laboratory experiments to help astronomers understand observational data. Bowen was teaching courses at Caltech when, in 1946, Carnegie President, Vannevar Bush, chose him to direct the Mount Wilson Observatory, the first physicist to do so.

19Young physicist, William Baum gained much of his experience in electronics working for the military during and immediately following World War II. His graduate education at Caltech was interrupted by the war, but through his service for the Navy, learned to develop instrumentation, both electronic and optical. He returned to Caltech where he completed his PhD in physics.

20The elder Bowen hired Baum to help Mount Wilson and Palomar astronomers use and develop electronic instrumentation. Baum developed photoelectric photometers—devices that measured the brightness of a galaxy, star, or planet as a single value. Joel Stebbins had developed photometers using photovoltaic cells as early as 1907. Stebbins and others moved on to the pursuit of photoelectric cells in the 1920s, and then photomultiplier tubes (PMTs) in the 1930s and 1940s (Miles, 2007). During this time, astronomers developed PMTs that could detect light in the ultraviolet and infrared. When Baum arrived at Mt. Wilson, he developed a photometer that could count individual photons. With this device, he helped astronomers use the 200-inch telescope to obtain photometry of stars as faint as 23^rd magnitude (Baum, 1954). One drawback to this method was that a PMT was a single-channel detection, it only provided a singular brightness and did not allow for measurement over a two-dimensional area of the sky. After developing a successful photoelectric photometer, Baum wanted to development a photoelectric area detector to rival the use of photographic plates alone on the 200-inch.

21Bowen and Baum had similar backgrounds. They had studied physics and developed optical instrumentation. They also both believed that electronic instrumentation, which had been spurred on in development by wartime needs and resources, could be used to push astronomical observations deeper and dimmer. Bowen and Baum differed, however, in how they viewed the role of the Carnegie Institution in taking a larger leap in the development of electronic imaging. Baum actively pressed for the immediate development of two-dimensional photoelectronic imaging at the Carnegie Institution. Bowen was restricted by the environment in which he became director. He felt pressure from his staff to prioritize efforts towards astronomical research using the world’s largest telescope, Palomar’s 200-inch. According to Bowen, the development of area detectors should be left to commercial industry. Baum, on the other hand, believed that a commercial company could not be relied upon to manufacture these devices, which became known as image tubes, to meet astronomers’ technical needs.

22Baum had to wait until the fall of 1953 to propose image tube development to Carnegie Institution president Vannevar Bush, when he made his annual visit to Pasadena. During these trips, Bush would casually visit with the scientists and technical staff, getting updates on work and offering to listen to advice or complaints. When Bush stopped at Baum’s office, Baum updated him on his instrumentation development efforts and argued that the next step should be to expand this principle to imaging. Baum detailed the current state of the field and outlined ways he felt Carnegie could improve upon those methods.

23According to Baum, Bush seemed interested in the idea, but did not say much until the following day, when Baum was called to Bowen’s office (Baum, 2004). As Baum recalled decades later, he walked in to find Bowen and Bush discussing photoelectric image devices and Bowen feigned ignorance. Baum recalled, “of course he knew perfectly well we’d been discussing it. So, I went through my spiel again and said that I felt that there was a big advantage here…It was the equivalent to building much bigger telescopes if you could pull it off” (Baum, 2004). Baum recalled Bowen that Bowen replied with his same argument for letting industry tackle the problem first: “these are very expensive things and beyond our engineering capacity and we have to let firms like RCA develop them to a later stage before we should get our feet wet.” Baum later learn that Bush took his proposal back to Washington, D.C. to see what might be done to organize sufficient talent and funding to carryout of development plans as Baum had described. This episode was critical in the formation of a committee devoted to developing image tubes in astronomy. Baum was confident in his assessment of the opportunity for technical advances and believed Carnegie should play a role in that process. By sharing these beliefs directly with Bush, paired with Bush’s concern for the scientific prestige of the U.S. and of the Carnegie Institution, they were able to successfully spur on the development of image tubes for astronomy.

24After Bush’s visit to Mount Wilson and his discussion with Baum, Bush and Bowen corresponded frequently. Initially, the two proposed that Carnegie collaborate with Electric and Musical Industries (EMI) while simultaneously establishing a U.S. group, with the U.S.-based group led by Department of Terrestrial Magnetism (DTM) director, Merle Tuve. As Director of a prestigious observatory, Bowen’s concern was the time any development efforts would require of his staff. Tuve, like Bowen, was hesitant about overburdening his staff with a new venture, but rather than dismissing the project, he offered to help, given the ability to add a few staff members to assist. Bush believed they would need someone from the television industry, like EMI, with knowledge of scanning systems, but Tuve suggested any devoted technician, who was competent in photoelectric performance of materials and their construction would be an acceptable substitute.

25The Carnegie Corporation of New York, a separate philanthropic entity established after the Carnegie Institution of Washington, granted Bush $50,000 and he formed a committee to begin work investigating the potential benefit of image tubes in astronomy. When EMI declined collaborating with Carnegie, Bush was happy to keep the project focused within Carnegie, as a way to promote the development of American science. With the Carnegie funds in hand, he made Merle Tuve the chairman of a new committee, informally named the Carnegie Image Tube Committee (CITC).

26With his connections and awareness of the state of U.S. science, Vannevar Bush was able to identify potential contributors to this development project. At the United States Naval Observatory (USNO), Bush found John S. Hall, an astronomer who had the right experience and characteristics. Hall earned his PhD in astronomy from Yale University and became director of the Astronomy and Astrophysics division of USNO in 1948. Beyond being skilled in electronics work and having an interest in electronic imaging, Bush specifically noted that Hall was a “delightful individual to work with,” a quality seemingly important to Bush as he assembled his team (Bush, 1953). Additionally, the commandant of the Naval Observatory was willing to collaborate with Carnegie, even offering space and technical aid. In John Hall and the USNO, Bush found a very willing and capable partner for Carnegie.

27Bush similarly inquired with Washburn Observatory director Albert Whitford about having one of his skilled astronomers, Art Code, spend up to a year at DTM, “with the idea that Code might be the man to really embrace this project” (Tuve, 1954). Code however declined the offer. At the nearby National Bureau of Standards (NBS), Bush located a physicist, Ladislaus (Bill) L. Marton, who was becoming well known for his work in electron microscopy. Marton was an engineer at the RCA research laboratories in Camden, New Jersey before founding the Electron Physics Section at the National Bureau of Standards (NBS). Bush noted that Marton was also interested in applying his knowledge of electrostatic focusing methods to the problem of electronic imaging for astronomy. NBS, like USNO, was happy to collaborate with Carnegie on the development of image tubes for astronomers. By attaching an astronomer to the project which also had one of the leading authorities in electron microscopy, Bush gave the pursuit increased credibility in the astronomical community.

28The CITC mostly worked independently from their home institutions, but they shared progress and discussed paths forward. They regularly communicated via letter and Baum, the furthest member, frequently traveled to Washington, DC to meet with the others. The Carnegie annual report, the Year Book, became their prime method for disseminating information in the first few years.

3.  Developing a New Technology

29In their first year of operation, the Carnegie committee, encouraged and supported image tube development already in progress, but they found most efforts would not satisfy astronomers’ low-light level requirements. Through these early discussions with commercial firms, however, CITC members realized they would need to direct the course of development efforts if they hoped to find a device that would help astronomers detect fainter objects. Many factors contributed to the first avenues the CITC members pursued. Each type of image tube had the potential to solve the problems astronomers were interested in—such as analyzing dim galaxies. Technical concerns appeared most prominent in early Committee discussions, but arguments about technical specifications were often compounded with social and economic concerns.

30After consulting with French astronomer André Lallemand during one of his trips to the United States, the committee determined that a tube they produced would need to be significantly easier to use than the Lallemand system. In deciding on which tube system to develop, the CITC had to consider the availability and location of resources, most importantly, technical staff.

31The CITC embarked on a 10-year effort, in attempted collaboration with industrial laboratories and the astronomical community to design and construct a device that would meet the needs and goals of all three groups. In a grant report for the Carnegie Corporation, the CITC wrote, “The requirement for a manufacturable device necessitated the interest and participation of commercial firms from the start,” but they struggled to find a company whose staff understood the needs of astronomers (Carnegie Image Tube Committee, 1958). Throughout this process, the Carnegie group attempted to disseminate information about image tube technology and their progress through publications and conference presentations. Through these promotional efforts, the Committee attempted to form a relationship between the builders and the potential users of this technology, but they struggled to provide an avenue for two-way communication that was acceptable to many astronomers. Their failure to engage the astronomical community in a dialogue, rarely listening to feedback concerning various development paths resulted in a user group without meaningful buy-in on the final product.

32The first signs of pushback from astronomers came after the 1958 Moscow meeting of the International Astronomical Union. Like the prior meeting, 1955 in Dublin, a special session was devoted to photoelectronic imaging and the CITC presented their status, along with members of the other groups from the United States, France, and Russia. After the meeting, Michigan astronomer, Leo Goldberg, in a report on the IAU, expressed his concern that the French and Russians were further along in development compared to the U.S.-based groups. CITC chair Tuve replied directly to Goldberg, expressing his own frustration with Goldberg’s response and others he had seen to the development of image tubes. Since André Lallemand had built the first image tube for astronomy two decades prior, some astronomers thought image tube development should have been more progressed. Tuve defended his group against the accusation of being too slow in their progress, arguing that there was nothing stopping any astronomer from using the French tube even though it was the CITC’s impression that this camera would be “suitable only for enthusiastic specialists” (Tuve, 1958b). The CITC, Tuve argued, was directing their efforts towards a device that more could use, despite prior knowledge and experience. The CITC had established at their start that they wanted to design a robust, easy-to-use image tube that could be used by any astronomer, but astronomers, as evident by Goldberg’s report, wanted something sooner.

33At the IAU meeting, Russian scientists presented tests performed with mica-window tubes, which were not, as Tuve informed Goldberg, a new device. The CITC had investigated mica-window tubes and described their development efforts in the annual Carnegie Year Books, a publication which did not attract a wide readership. The mica-window tubes were, in fact, available for immediate use by astronomers, but the CITC abandoned further development because of their poor resolution. Tuve contended with Goldberg, suggesting:

If we supply you with a tube such as the Russians used, I honestly believe you would test it for half a day or so and set it aside. If we supplied you or your colleagues with a Lallemand tube, with sealed-off cassettes of fresh cesium surfaces, I am confident its best use would be as an exhibit on the Observatory shelves. (ibid.)

34“Our Committee,” Tuve argued, “was not endeavoring…to make any grandstand plays” but was interested in producing a “genuinely useful astronomical tool for wide regions of the spectrum” (ibid.). Though frustrated by the dissatisfaction of astronomers, Tuve did conclude his letter, however, with a diplomatic request for feedback:

I write this somewhat reluctantly, as I feel rather immune to criticism of astronomers regarding image tubes, but I recognize that our committee is vulnerable, and especially the two astronomers on it. If you can help us make the United States astronomical leaders, somewhat less discontented with the present situation, I will appreciate your suggestions. (ibid.)

35Tuve was relatively reserved in his letter to Goldberg in comparison to his plea to Ira Bowen, writing,

I suppose our committee should be content to be lambasted by our American friends, but I am strongly tempted to throw the ball right back at them with the reminder that no great help was forthcoming from the ranks of astronomers either for our efforts or for [Albert] Hiltner’s. (ibid.)

36Tuve was frustrated that the CITC could not secure the services of a young astronomer to assist with the tedious labor of testing tubes at the telescope. In every attempt they made to recruit a young astronomer, they chose to work for Aden Meinel at the University of Arizona, who could outbid the CITC with an offer of a permanent position. “The gist of my position,” Tuve wrote, was “that we deserve to be spanked if we have been slow-pokes, but the spankers would be more constructive if they would find us at least one young astronomer willing to take a job with our committee” (ibid.).

37Bowen acknowledged that he had received several reports from astronomers after the Moscow meeting. Though he did not specify which astronomers had approached him, he suggested to Tuve that either the CITC had not been fully promoting their own accomplishments like the French and Russian groups, or American astronomers did not fully comprehend the technical problem they faced. While creating an image tube that could produce large amplifications of light was relatively easy to accomplish, Bowen recognized that the CITC’s goal was bigger; they hoped to create a tube that would result in a large application of the light intensity, while also maintaining resolution of the original image, and be easy to operate in an observatory setting. Bowen suggested appointing an advisory committee where the main focus would to be educate the astronomers of the development work and provide updates. His goal didn’t imply a search for advice, but his focus on education again shows the focus on the dissemination of information rather than having a dialogue. Both Bowen and Tuve seemed to suggest that if astronomers knew the true state of affairs in the development of image tubes generally at and the CITC, they would be satisfied with the suggested destination and the progress.

38Suggestions of ways to improve the CITC’s outreach were not received with much consideration by Merle Tuve. He argued that the outcry from astronomers was not due to their frustrations with the U.S. group’s lack of progress, but their eagerness to use one of these devices as soon as possible. Because of this, Tuve concluded, there was no need to consult with astronomers as to the direction of development. Instead, he argued, time should be dedicated solely to the rapid development of an image tube they can get into the hands of astronomers. This assessment contradicts Tuve’s letter to Goldberg, which insinuated that a large problem was that Goldberg and other astronomers did not have a good grasp on the problems facing image tube developers. Instead, Tuve seemed to be arguing that the CITC was on a good path and did not need to be slowed down by communicating directly with astronomers beyond occasional published articles, conference presentations, and yearly Carnegie reports.

39The resistance from both groups of users, the CITC and the astronomical community, to work together to determine a common goal and plan is evident in this correspondence. Informally, CITC astronomers John Hall and William Baum discussed the problems and solutions with other astronomers, but the formal consultations were directed by Tuve who felt that the CITC and Carnegie had internal access to astronomers who could speaker for the community. As a result, the CITC did not formally engage the astronomical community, though Baum and Ford continued to present at conferences, often to other physicists working of similar problems, and learn from astronomers as they passed through observatories, conducting test observations. In development efforts, the CITC continued to work towards their goal without any official sway from the astronomical community.

4.  An Instrument for All and for None

40The original CITC members had established their goal in 1954 to develop a rugged electronic device, with enough gain to be beneficial for astronomers, but whose operation was simple enough to be employed by any astronomer at any observatory, particularly those with access to only modest-sized telescopes. By the start of 1964, after a decade of research and development efforts by scientists and engineers at DTM, Mt. Wilson and Palomar Observatories, Lowell Observatory, the U.S. Naval Observatory, the National Bureau of Standards, RCA, the International Telephone and Telegraph Company (ITT), and Imperial College London, the CITC believed they achieved that goal. With funding from the National Science Foundation, championed by Vannevar Bush, the CITC contracted RCA to produce two types of image tubes that the group believed were ready for regular astronomical use: a mica-window converter and a cascaded image intensifier. The mica-window converter had been developed during earlier phases of the CITC, and though they were at a standard the CITC hoped for, they were useful for astronomers wishing to observe in the infrared. The cascaded image intensifier was Carnegie’s general-use image tube and was particularly useful in the blue portion of the spectrum. The cascaded intensifier was produced in higher quantity than the mica-window converter and became known as the Carnegie Image Tube.

41The first run of Carnegie Image Tubes each cost $5,000 to manufacture but was provided free of charge to astronomers. Between 1965 and 1968, the CITC loaned Carnegie Image Tubes to 34 observatories around the world. Of the tubes that were allocated, some were used actively by astronomers, some garnered intermittent use, and some were largely neglected. The CITC worked with astronomers and observatory staff to support use of the Carnegie Image Tube, but struggled to help the tube find widespread, regular use.

42In December of 1967, Lick Observatory astronomer Tom Kinman requested a replacement tube after their tube began to produce so much spurious background noise, it became useless for any observational program. Kinman wrote,

43We have tested it in the same spectrograph as the other Carnegie tube which we possess and find that the background is quite excessive even at 17,000 volts. Apparently, the background is so bad that the test spectrum was swamped and we do not know whether a focus is obtainable. The tube has therefore been packed ready to return to you…Needless to say I was very disappointed in the performance of this tube and I hope that it will be possible for another tube to be made available. (Kinman, 1967)

44Ford responded quickly, equally disappointed at the tube’s failure, but suggested it was inevitable that some of the tubes would be faulty or would degrade over time. Kinman was frustrated again when, within six months of receiving his replacement tube, the new tube again began to produce spurious background noise, limiting any possible benefits to the tube’s use. Ford was sympathetic and likewise frustrated, noting that Kinman’s tube was producing backgrounds unlike any he had ever encountered. Ford could not find a reason for the tube’s failing and recommended that Kinman look to purchase a tube directly from RCA, as the CITC had no additional spare tubes to lend. It is unclear whether Kinman purchased additional tubes from RCA, but he never obtained scientific results with the Carnegie Image Tube from which he was able to publish any scientific results. Even skilled operators, like Kinman, encountered problems with image tubes in practice, likely in part due to the inability of the RCA laboratories to produce a standardized tube to the CITC’s specifications.

45At Mount Stromlo Observatory, located near Canberra, Australia, interest in the Carnegie Image Tube came largely from Theodore Dunham, who had worked at Mount Wilson Observatory, developing spectrographic instrumentation. Kent Ford traveled to Australia to assist in the installation of the image tube system and, according to a 2013 interview with Kent Ford, Dunham was more interested in getting the image tube assembly than in using the device for scientific research. Ford trained both Dunham and Kurt Gottlieb, the Observatory’s instruments manager. Ford noted that he had no issues training Dunham nor Gottlieb, but had heard later that Gottlieb was contentious, which created issues with the use of the image tube at Mount Stromlo. Whether it was a result of the instruments technician being difficult to work with, only one scientific paper was published with the equipment in Australia, though that paper was highly cited (Wegner, 1973).

46Astronomers published results in the immediate years after allocation from several observatories, including the University of Wisconsin (Code, 1967), Harvard College Observatory (Page, 1967), University of Texas (Bergstralh & al., 1967). Image tube use slowed considerably through the 1970s, but infrequent use still occurred, including up until 1980 at the Cerro Tololo Inter-American Observatory in Chile (Moffat, 1980). Many of these papers are a review of the instrument, but some produced scientific data.

47The most successful use came from Carnegie staff members Vera Rubin and Kent Ford, who shared an office at the Department of Terrestrial Magnetism campus. But even Rubin, when first offered to use a CCD spectrograph, opted to move away from the image tube, and CCDs soon became the standard method of imaging in astronomy.

5.  Conclusion

48In short, the Carnegie Image tube received mixed results, and the earlier hope that the Carnegie tube would replace photography alone was dashed. The Carnegie group was unsuccessful at meeting the goals they had established at their formation. But they laid the groundwork for a new era in observational astronomy by showing that there was a benefit of more sensitive and efficient two-dimensional detectors in astronomical research. The full scientific impact of the Carnegie program is currently being studied by the author.

49In attempting to serve as a conduit between the producers of image tube technology and the potential users of that technology, the CITC had to compete for commercial resources and contend with choices made by individual astronomers. The efforts of the CITC show how the backgrounds of several key physicists influenced the direction of image tube research at the Carnegie Institution and how the concern of scientific prestige led the Carnegie Institution to decide to investigate image tube technology. The increase in US federal funding helped this effort sustain itself through two decades of development. A one-size-fits-all approach, however, could not ultimately contend with the technical skills, observing habits, and research needs of disparate groups of astronomers working on a variety of projects at different wavelengths and sensitivities. While the CITC’s efforts did not result in an overwhelming adoption of image tubes by the astronomical community, by examining how the Carnegie image tube was produced, funded, and marketed, this story can help shed light on the many and varied processes through which astronomers have acquired or ignored new tools.