Apollo & the BAA Lunar Section

2019 May 25

Bill Leatherbarrow

With the launch of Apollo 11 on 1969 Jul 16, humankind embarked upon its greatest voyage of discovery. The successful landing of two men on the surface of the Moon some four days later was the end result of more than a decade of intensive technological preparation as launch vehicles, rocket modules and orbital/landing techniques were refined. But apart from the development of the Apollo hardware, other preparations for a manned landing had been running in parallel.

The dawn of the Space Age, and the start of superpower rivalry in a ‘space race’, focussed the attention of professional astronomers on the need to develop reliable maps and atlases of the lunar surface. Key results were eventually achieved by the US Air Force at the Aeronautical Chart and Information Centre, by the US Geological Survey, and through the work of Gerard Kuiper’s team – first at Yerkes Observatory, and subsequently at the University of Arizona with the foundation of the Lunar and Planetary Laboratory. During the late 1950s and early 1960s these teams saw the development of new aeronautical and geological maps and atlases. These were based upon the best available photographs and drew upon the skills of experienced, professional cartographers. Not only were they much more accurate than any previous maps of the Moon, they were also fit for the new purposes of the Space Age.

The Section pre-Apollo

Before the advent of the Space Age and the consequent growth of professional interest in the Moon, the task of mapping our satellite had fallen largely to amateur visual observers using modest telescopes. The role of the BAA Lunar Section during this period had been second to none. The maps produced by its first two Directors – Thomas Gwyn Empy Elger (1838–’97) and Walter Goodacre (1856–1938) – were among the best of their time, and the achievements of both have been officially recognised in the naming of two lunar craters after them.

Nevertheless, amateur lunar cartography during the first half of the twentieth century had been severely hampered by certain factors. First of all, such observers were reliant upon their individual skills in visual observation and draughtsmanship, inevitably introducing an element of subjectivity no matter how carefully they worked. Secondly, few of them were familiar with the techniques and competences of the professional cartographer.

However, by far the most important limitation on their achievements was imposed by the very philosophy underlying their endeavours. From the age of Elger, if not before, excessive emphasis had been placed upon the recording of finer and finer detail as revealed by larger and larger telescopes, at the expense of paying due attention to the larger structures of our Moon and their meaning. This emphasis arose from a preoccupation with the possibility of small-scale changes on the Moon and the need to establish highly detailed reference charts, against which such suspected changes could be measured. Such work was not entirely without value, and many outstanding observers from the BAA Lunar Section contributed to it in the decades either side of the Second World War. But in the longer term the devil did reside in such detail. The 300-inch map completed in the 1950s by Hugh Percy Wilkins, Director of the Lunar Section from 1946–’55, was so overwhelmed with masses of tiny (and often spurious) detail that it was uninterpretable even by fellow telescopic observers, let alone by future mission planners and astronauts looking for workable charts to guide them around the lunar surface.

It is therefore probably true to say that from the late 1950s, a gulf opened up between amateur and professional approaches to lunar cartography. Apparently Wilkins’ maps were used by the Russians in 1959 as they sought to make sense of the first grainy photographs of the Moon’s far side returned by the spacecraft Luna 3, but that was the last time that maps based primarily on visual observation played a role in spacecraft-based exploration. Indeed, Wilkins’ 300-inch map should be seen as marking the end of an era in amateur Moon-mapping.

Yet, despite this, the BAA Lunar Section went on to make significant contributions to the development of the American Moon program, albeit in ways that were indirect and unexpected.

A new era

Wilkins’ successor as Director was Ewen Whitaker, an astronomer who worked at the Royal Observatory, Greenwich. His professional work there was in astrophysical and astrometric programs, but since the early 1950s he had developed a strong ‘amateur’ interest in the Moon. As Director, Whitaker tried (not entirely successfully!) to steer the Section towards a more ‘scientific’ approach to lunar cartography based to a greater extent on photographs taken at professional observatories.

In 1955 BAA Council awarded him a small grant in order that he might attend the Ninth Congress of the International Astronomical Union held in Dublin, along with fellow BAA member Alan P. Lenham. At that congress Gerard Kuiper (then President of IAU Commission 16, on ‘Physical Observations of Planets and Satellites’) distributed a memorandum emphasising the need for a new lunar atlas, based upon high-resolution photographs, as a basis for future research and exploration. He also called for comments on and criticism of his proposals. Whitaker was the only delegate to respond, and that provided the basis for a developing professional relationship between the two men. As Whitaker later wrote: ‘Kuiper was clearly delighted to find someone who had a strong mutual interest in his proposals, and we maintained a regular exchange of letters from then on. He informed me of any progress, new ideas, changes, etc., some of which he had reached as a result of discussions with Lenham’.

Following the Dublin congress, Lenham was invited to join Kuiper at Yerkes as a research associate, the first of a small exodus of BAA members invited to participate in Kuiper’s lunar and planetary projects. As Kuiper’s Moon atlas work developed Whitaker was increasingly asked to contribute, along with a fellow member of the BAA Lunar Section, D. W. G. Arthur. Recommended to Kuiper by Whitaker at the Dublin congress, Arthur had a particular interest in lunar crater typology and distribution, as well as professional expertise in cartography via his work with the Ordnance Survey. He was also the first editor of the Lunar Section bulletin The Moon (now available online to BAA members at: https://britastro.org/downloads/11775).

All this culminated in 1958 January when both Whitaker and Arthur received letters from Kuiper, inviting them to accept formal positions at Yerkes as research associates working on the lunar atlas project. Both accepted and moved permanently to the USA. It is a measure of Kuiper’s unorthodoxy and willingness to trust his own judgement that he would readily engage lunar ‘amateurs’ based upon what they had achieved and the ideas they advanced, rather than upon formal academic qualifications. Both Whitaker and Arthur repaid Kuiper’s trust in full, developing new mapping techniques and collaborating in the production of the best and most accurate photographic atlases, including a rectified atlas that compensated for the apparent foreshortening of lunar features as seen from Earth.

Whitaker, in particular, went on to become one of the most esteemed lunar scientists of the twentieth century, playing an important role in the American Moon exploration program as it built towards the successful landings of the Apollo era. He was involved in the Lunar Ranger project, selecting the impact sites for Rangers 6 & 7. He also contributed to the selection of the Apollo landing sites and helped to brief astronauts on Apollo 13, 15 & 16. Perhaps his most striking accomplishment was tracking down the exact location of Surveyor 3, allowing the Apollo 12 astronauts to land close by and retrieve the camera from the earlier mission. For this he received a letter of commendation from President Richard Nixon.

The Section evolves

The ever more rapid development of the American lunar program during the 1960s had a very significant impact upon the work of the BAA Lunar Section. Initially the results achieved by the Ranger and Lunar Orbiter missions provoked not just excitement but also something akin to despair, as many observers came to the conclusion that the day of the amateur was drawing to a close. Certainly, the missions demanded that amateur lunar observers should take a long, hard look at what they were doing if their role was to remain relevant. Not only could such missions produce high-resolution imagery of the lunar surface that instantly rendered amateur charts redundant, but they also revealed the fallacy behind the amateur’s pursuit of ever-smaller topographical details – namely that such a pursuit was an endless game of tail-chasing. The imagery returned by the Ranger probes before impact left no doubt of the simple truth that the closer you got, the more small detail you saw.

Even before the Ranger and Orbiter missions, this truth had been recognised by some within the Lunar Section. Whitaker’s successor as Director, the professional geologist Gilbert Fielder, tried to steer the Section’s observers away from detailed mapping of their pet areas and towards consideration of types of lunar feature and how they were distributed across the Moon’s surface. Special charts were produced, thanks to a grant from BAA Council, that allowed observers to plot the location of such geological structures as rilles and domes. However, it must be said that – as was the case with Whitaker’s proposed reforms – Section members were reluctant to respond to Fielder’s perfectly reasonable innovations. Most just carried on mapping in the tradition of Elger and Goodacre.

Others in the Section took the view that since the Moon’s permanent topographical features had now been charted so effectively by spacecraft, then the task of the amateur should shift towards the study of transient events. During the mid-1960s, under the directorship of Patrick Moore, huge interest was generated in the observation of TLP (transient lunar phenomena, such as temporary glows, colours and flashes). Hundreds of reports of suspected activity were submitted, often by inexperienced or unwary observers, and there is little doubt that in many cases enthusiasm got the better of judgement. However, the TLP program gained credibility from the support of some American professionals, in particular Winifred Cameron and Barbara Middlehurst. The latter had worked with Kuiper, who nevertheless remained somewhat less than convinced of the reality of TLPs. Further professional validation appeared to come in 1963 October, from the observation of suspected activity near the crater Aristarchus by Edward Barr and James Greenacre at Lowell Observatory, Flagstaff. TLP observation was also encouraged by the later establishment of NASA’s Lunar International Observers Network (LION). This mobilised amateur observers to monitor the Moon for changes during the various Apollo missions; many Lunar Section members, including myself, took part.

The TLP program went on to dominate Lunar Section activity for the next few decades, ironically at a time when results from Apollo and other missions were increasingly persuading professionals that the modern Moon was to all intents and purposes geologically inactive. It is still part of our work today, but now the emphasis is on the observation of impact flashes (which are certainly real) and on careful repeat observations in order to establish the reality or otherwise of past reports, discounting them when necessary.

The legacy of Apollo

In 1969 June, with the Apollo 11 mission imminent, Ron Maddison – then Director of the Lunar Section – wrote in the Lunar Section Circular that the Moon was yielding up its secrets rapidly, ‘but it is our problem to accept the new information and adapt our techniques’. Two months later in the August issue he followed this up, saying: ‘We, as individuals [in the BAA], do not have the opportunity to shake the world with astounding results […] but we still have the opportunity to solve some of the many intriguing problems and to interpret many of the new results’.

His words were well chosen. Today’s Lunar Section has learned, from Apollo and its aftermath, what it can and cannot contribute. Our members have successfully adopted the technical developments that now allow us to image the Moon with unprecedented accuracy, detail and insight. We have also learned to take advantage of professional results and datasets, freely available via the Internet, to supplement our own telescopic observations and enhance our interpretation of the Moon’s surface features.

We cannot, as Ron said, shake the world or operate at the frontiers of lunar science, but we can generate useful and informative results – perhaps to a greater extent now than was possible before Apollo changed everything.

Bill Leatherbarrow, Director, Lunar Section