Russell W. Porter at Caltech

As early as mid-1930 Porter had clear design ideas about what was to become the Hale Telescope dome. Porter’s first studies echoed neo-classical observatory forms but established a geometry concept with the telescope’s two-axis articulation point (formally the point of closest approach of the right ascension and declination rotational axes) at the center of an encompassing sphere. Porter also developed building plans for campus buildings that would support Palomar development: the “Astrophysics Laboratory” that would later become Robinson Laboratory (slide 4) and the optical and machine shops (slide 5). These activities made Porter the key project contact for the emerging 1930s Caltech campus architecture under the guidance of architectural firm Goodhue & Associates ^[sp18].

Project delays developing the 200-inch telescope primary mirror technology created the opportunity for Porter to become involved in Griffith Observatory concept development and design at Hale’s request starting in 1931. This in turn brought Porter into direct contact with Griffith Observatory architects John C. Austin (designer of L.A. City Hall and Shrine Auditorium) and Frederick Ashley (designer of LA Public Library Memorial Branch and Monrovia High School) in the midst of the early 1930s Art Deco period in Los Angeles. Porter’s 1931 Griffith studies were influential in the final designs adopted by Austin and Ashley ^[c94], and it is reasonable to infer that Porter’s consulting on the Griffith project (along with his activity on Robinson Laboratory in conjunction with Goodhue architects during this same period) informed Porter’s influences along the lines of Art Deco and Greek threads apparent in the iconic Griffith design (slides 2 and 3).

Little is definitively known about Porter’s Palomar architectural development in the period 1933–1934: he seems to have been more focused on questions of telescope design (Design, slides 6 and 7). However two studies from this period suggest different aspects of Porter’s thinking on possible Palomar dome architecture. First is “The Modern Archdome” dated 1933, perhaps based on a suggestion by Francis Pease and Romeo Martel. Probably just intended by Porter to be a notional sketch, the archdome concept is clearly evocative of Art Deco designs that were prominent in the architectural landscape of the early 1930s. Second, an undated study (slide 8; ca. 1934-35) depicting the 200-inch dome and flanking buildings. Porter himself superposed a circle to illustrate that the conceptual base of the dome's encompassing sphere is placed at ground level. These same structural proportions were realized in the as-built Hale dome; Scientific American editor A. Ingalls is credited with first noting the dimensional and proportional similarities between the Hale dome and the iconic Roman Pantheon ^[w54].

By 1935 direction emerged in Hale dome design that combined clear influences from the Griffith project (i.e. enclosed dome shutter support rails) and the 100-inch Hooker Telescope dome at Mt. Wilson featuring windows and bevels in the dome shutter doors (slides 9 and 10). The basic concept of what was to become the Hale dome is captured in a 1935 Palomar site sketch with a hemispheric dome (presumably still centered on the telescope articulation point) supported by a cylindrical substructure, and incorporating the same “Pantheon proportions” depicted earlier. From 1935–1937 Porter codified these designs in a series of physical models—one of which was used as cover illustration in an early 1936 Scientific American article ^[m36] (slide 11).

By mid-1936 the 200-inch dome design was considered sufficiently mature to justify ground breaking at the Palomar site (slide 13). During the second half of 1936 progress on the telescope and dome substructure was rapid (e.g. the concrete observing floor was in place by New Year’s Day 1937). Meanwhile Porter studied dome architectural details, and late in 1936 Porter reviewed Hale Dome architecture concepts with the Observatory Council, including drawings and physical models ^[p36] (slides 14 and 15). One of these models (on exhibit in Palomar’s Visitor Center) shows a variety of architectural accents on the cylindrical substructure and dome superstructure—as if to illustrate possible accent choices for Council consideration. By April 1937 the Hale dome design was complete and communicated to the contractor—Consolidated Steel of Los Angeles (slide 17). During most of 1937 the dome steel superstructure and monocoque shell was constructed, and during this time the first Porter drawing with the Hale Dome as built emerged (slide 18). An Art Deco-influenced “terraced” dome shutter design evocative of the early “archdome” study had replaced the circa 1935 beveled/Hooker treatment. By early 1938 the upper dome construction was essentially complete and being fitted with the rotation trucks.

By mid-1938 the Hale dome could rotate on supporting trucks, and exterior painting began while the dome interior was fitted with the aluminum inner skin integral to thermal management. During this same period plans were finalized for the 48-inch Schmidt (later the Samuel Oschin Telescope) dome, and Hale dome themes and proportions were incorporated into that design as well. With the dome designs finalized Porter could focus on his portfolio of Palomar dome and telescope “cutaway” drawings—which many consider to be his most important and lasting observatory contribution. The Palomar project apparently knew a good thing when it saw it: the drawings soon became central in internal and external project communications.

Porter’s campus and Palomar observatory designs have been called “characteristic[ally] Art Deco” ^[f94], and there are clearly recognizable Art Deco influences in Palomar architecture. But the reality is somewhat more subtle: while some aspects of original Porter studies found their way into the final Palomar designs, they also show considerable stylistic evolution incorporating a diverse set of influences. What is clear is that Porter found himself immersed in the 1930s Los Angeles Art Deco movement, and had extensive contact with prominent Art Deco architects throughout the early 1930s—particularly through involvement with Caltech campus and Griffith Observatory project. It’s reasonable to infer these influences shaped how Porter imagined the eventual architectural themes expressed at Palomar Observatory.

Astronomical telescopes were among Porter’s many passions, leading him to found the famous Springfield Telescope Makers organization and its Stellafane headquarters in 1923. Porter reportedly came to Hale’s attention through a series of articles on telescope making appearing in various publications including Popular Astronomy, Amateur Telescope Making, and Scientific American ^{[w54] [w76] [f94]}. Biographer Bert Willard reports that Porter and Hale met in early 1928 over dinner arranged by a mutual friend (Albert Ingalls), and the conversation focused on ideas for large telescope design. By the fall Hale actively sought to recruit Porter to the just-funded 200-inch telescope project and by late that year Porter traveled to Pasadena.

Soon Porter was discussing and drawing engineering concepts for the new large telescope. Early telescope concepts ca. 1929 started with the prior art of the “Victoria” mount. A guiding principle adopted by Hale was to avoid the geometric limitations of the 100-inch Hooker Telescope that could not point at the Celestial Pole. Pease assumed cognizance for the telescope mount design and was an advocate for a “fork”-type mount (closely related to a 1918 Porter publication employing a “split-ring” geometry ^[p18]), but structural analysis suggested the fork scaled to the anticipated mass of the 200-inch telescope would express significant flexure.

During the early 1930s multiple people including Pease, Porter, and external advocates Robert Edgar and H. Page Bailey (who went so far as developing a working model ^[c01]) apparently considered a yoke-type mount with separate support on the north and south ends of the telescope structure; an open “horseshoe” north bearing would retire the polar pointing restriction. Porter sketched a “spherical mount” including this horseshoe-yoke concept as early as 1932 (slide 6), but because the project was struggling to procure a viable primary mirror blank there was little immediate pressure to push the 200-inch design further. By 1934 mirror difficulties had been solved, and decisions about telescope design became urgent. In late 1934 scale models of the telescope structure using both fork and horseshoe-yoke arrangements had been developed, and by spring 1935 the Observatory Council had approved the yoke configuration ^[m39]. Hale reported in the literature on the horseshoe-yoke model (slide 7) as the preferred concept ^[h35], attributing it to “[John] Anderson, Edgar, and [Mark] Serrurier”, but there are reasons to believe Porter was also involved in model development. Over the next two years key refinements of the telescope structure to as-built form were led by Serrurier (yoke structure simplification and “Serrurier Truss” telescope tube) and Rein Kroon (declination trunnions and oil flotation). By mid-1936 the 200-inch design had converged to something closely resembling the as-built telescope (slide 12).

Concurrent with the 200-inch design in 1934 Porter became cognizant for the 18-inch Schmidt telescope design (an observatory addition advocated by Walter Baade and Fritz Zwicky and approved by Hale). Porter chose the traditional simplicity of a fork mount for the new telescope—no doubt simplifying implementation on an ambitious timeline. By late 1935/early 1936 the 18-inch telescope was being fabricated in the Caltech shops (slide 13), and the dome to house it was designed and construction contracts issued; first light for the telescope was September 1936. The telescope was immediately productive; Zwicky discovered several supernovae in the first few months of operation.

While several individuals contributed important components to the 200-inch telescope design, Porter’s contributions to the design process were central. He had years before developed the “split-ring” garden telescope that was the logical predecessor to the horseshoe-yoke concept adopted for the 200-inch telescope. Porter had long been a prominent leader in the amateur telescope making community, and his leadership fostered enthusiasts like Edgar and Bailey who added to the consensus around and demonstration of the as-built design. Finally, and probably most importantly Porter’s growing facility with technical illustration and modeling made him the de-facto nexus of the telescope design team, and the conduit through which design ideas were communicated and discussed.

With the 200-inch dome design activities winding down by mid-1937, Porter’s next formal assignment was unclear. Apparently self-motivated ^[w51] and contemporaneous with observatory construction Porter undertook to develop a series of technical illustrations to depict the observatory’s design and function. A detailed study of the 200-inch primary mirror and cell from 1937 was among the first of this series and captured the complex interplay of the mirror cell, support system, and the 200-inch mirror itself (slide 7). The next year Porter created the iconic meridional cross-section drawing of the Hale telescope and dome (slide 10). The growing series of drawings had the practical effect of making the structure and function of the emerging Palomar telescopes and buildings accessible to many audiences. Porter continued adding to the series for the next decade, with the majority of series activity in the period 1937 – 1941; World War II interrupted Porter’s focus on the 200-inch project in general and the illustrations in particular. Collectively these Porter drawings known as the Giants Collection have been celebrated in many contexts and remain an important and beloved part of Palomar’s and Porter’s enduring legacy.

Key to the Giants series acceptance was Porter’s mastery of the “cutaway” visualization method to expose the underlying structure of his subjects. Long a staple in technical illustration, Porter was introduced to the cutaway method while an architectural draftsman for MIT Professor C. Despradelle ^[w76]. Porter sketches as far back as 1929 evidence his emerging facility with the method in the context of Palomar design work. Particularly during telescope structural design activities from 1932 to 1935, Porter’s ability to envision and capture telescopes and structures long before they were built was extraordinary, and his early cutaway sketches enabled project engineers to visualize proposed designs and assess the complex interrelationships among components and subsystems. By 1937 Porter was a master of this cutaway method and used it to great effect in his Giants series. Giants drawings are highly faithful renderings, but small differences between the drawings and the as-built subjects (e.g. the lack of coudé arm lightweighting in “Looking North”) are a subtle reminder that Porter created the series before the Hale Telescope mount was built—making his art all the more remarkable.

Porter executed the Giants series on 4-ply 30×40-inch art boards. He used mainly graphite (pencil) of various hardness to define shape edges and shade areas, black ink for outlines and precision shadows, and a sharpened eraser or white ink for highlights. Most of the drawings are enclosed in a black gouache rectangular frame, but in a few Porter playfully breaks the frame off to one side to continue a detail of the drawing or to trace incoming light rays in white ink. The hand of the artist is evident in these drawings when seen in person (or in very high-resolution 1:1 reproduction): the handcrafted quality of the artwork in the strokes, the texture of the different media, lightly-traced lines lost in printed reproductions, and Porter’s extraordinary skill in representing complex three-dimensional engineering concepts is captivating to behold in the modern era of computer-generated illustrations. Two distinct drawings included among the Giants series are pastel representations of the Hale Dome from slightly different perspectives. The original Giants drawings are maintained at Caltech Archives; we find viewing them in person is a uniquely moving experience.

Records found among Anderson’s archived papers ^[u47] indicate that the tradition of decorating Caltech’s H. Robinson Laboratory of Astrophysics with Porter’s Giants of Palomar Collection began during the war years, and observatory staff would often refer to these drawings to understand and communicate nuances of telescope structure and function. Popular publications featured the Giants illustrations even as the series was still emerging ^[w39]. In 1947 the first edition of “Photographic Giants of Palomar” by engineer James Fassero and Porter (with a foreword by Max Mason) was published featuring 22 of Porter’s “technically sophisticated or cutaway” illustrations ^[agc]. Multiple “Giants of Palomar” editions ^{[f52] [p83]} continued until the early 1980s when the 11^th printing included text updates attributed to the observatory staff. At the time of this writing “Giants of Palomar” is out of print, but electronic records of this 11^th printing version are available through Caltech Library.

Porter’s Giants Collection has been treasured by generations of enthusiasts—technical illustrations making the inner workings of Palomar telescopes such as the Hale and Oschin accessible to a wide audience. But the Giants Collection is also venerated artistic expression. The American painter Maxfield Parrish is quoted as remarking on the Giants Collection ^[s39]:

If these drawings had been made from the telescope and its machinery after it had been erected they would be of exceptional excellence, giving an uncanny sense of reality, with shadows accurately cast and well nigh perfect perspective; but to think that any artist had his pictorial imagination in such working order as to construct these pictures with no other material data than blue prints of plans and elevation of the various intricate forms—is simply beyond belief. [...] I doubt if there are drawings anywhere which can in any way compare with these for perfection in showing what a stupendous piece of machinery is going to look like when finished. [...] Their creation should be world news.

Giants drawing collection elements are self-similar in technique (e.g. pencil and ink; cutaway), materials, large physical format (e.g. 40 × 30 in), and subject matter (Palomar Observatory). The extensive similarities make it reasonable to infer that Porter intended these drawings to comprise a cohesive set.


1. Two hundred inch mirror, cell, support & cover (1937)
2. South polar axis bearing, yoke & right ascension drive (1937)
3. Cutaway drawing of declination trunnion (1937)
4. The two hundred inch telescope (aka meridional cross-section, or key drawing, 1938)
5. Two hundred inch looking north (1938)
6. Mirror supports (1938)
7. The prime focus (1938)
8. The prime focus, Cassegrain and coudé mirrors (1938)
9. The two hundred inch telescope looking northwest (1939)
10. North polar axis bearing, horseshoe & oil pads (1939)
11. South polar axis bearing showing the oil flotation (1939)
12. The four foot schmidt photographic telescope (1939)
13. The prime focus housing and pedestal (1940)
14. Right ascension drive and computor (1940)
15. Declination drive and control mechanism (June 1940)
16. Cassegrain focus platform (1940)
17. Vacuum aluminizing chamber (1940-41)
18. The four foot schmidt photographic telescope (1941)
19. The 200 inch dome (pastel, 1942)
20. The two hundred inch dome (pastel, 1942) *
21. The 200 inch telescope looking east (1947)
22. Plate loading assembly, 48 inch Schmidt photographic telescope (1947)
23. The coudé mirror & crane (undated)
24. Coudé room spectrograph (undated)

* Location unknown