Ferdinand Ellerman
Ferdinand Ellerman, c. 1920
Born (1869-05-13)May 13, 1869 Centralia, Illinois Died March 20, 1940(1940-03-20) (aged 70) Los Angeles, California [1] Spouse Hermine Louise Hoenny [2] Children Louise [2] Parents
- Mathias Ellerman [2] (father)
- Rosa A. Fleischbein [2] (mother)
Ferdinand Ellerman (May 13, 1869, to March 20, 1940) was an American astronomer and, perhaps less notably but equally competently, a photographer. He spent a significant, almost symbiotic, portion of his professional life as an associate of the renowned solar astronomer George E. Hale. Ellerman is primarily acknowledged for his detailed study of a peculiar, transient phenomenon within the solar chromosphere, which was later rather dramatically dubbed Ellerman bombs. His contributions extended beyond mere observation, encompassing a practical acumen that proved indispensable in the nascent stages of modern astrophysics.
Biography
Ferdinand Ellerman arrived, presumably with minimal fanfare, in Centralia, Illinois, on May 13, 1869. He was the progeny of Mathias Ellerman and Rosa A. née Fleischbein [2], a fact that, while foundational, offers little insight into the man who would dedicate his life to staring at the sun. His early education led him to High School in Belleville, Illinois [2], after which he, somewhat unexpectedly, relocated to Chicago. There, he found employment at the James S. Kirk Company [3], a rather industrious enterprise specializing in the manufacture of soap [4] [5]. It was during this period, amidst the mundane creation of cleaning agents, that Ellerman honed skills that would prove surprisingly relevant to his future celestial pursuits. He acquired considerable proficiency in the operation and understanding of machine tools, alongside a keen eye and steady hand for photography [3]. These practical talents, often overlooked in the romanticized narrative of scientific discovery, would soon become the bedrock of his astronomical career.
In 1892, Ellerman was, for reasons that remain a testament to his understated capabilities, hired as an assistant by the already influential astronomer George E. Hale. This initial engagement was for observation work at Hale's private Kenwood Observatory in Chicago. This marked the inception of a professional partnership, a working relationship, that would endure for an impressive span of 46 years, continuing steadfastly until Hale's passing in 1938 [6]. Their initial encounter likely occurred during the inaugural meeting of the Chicago Section of the Astronomical Society of the Pacific in November 1890. It is even plausible that Ellerman's journey into professional astronomy began as a volunteer, a common, if often unacknowledged, path for those with more passion than formal credentials [7]. Ellerman, it appears, became the indispensable workhorse of this collaboration, executing a substantial portion of the painstaking observation work, thereby freeing Hale to dedicate his energies to more visible endeavors such such as travel, fundraising, and organizational activities [8]:10–11. On a more personal note, May 16, 1895, saw Ellerman marry Hermine Louise Hoenny. Their union would produce one daughter, Louise, who arrived on July 29, 1901 [2].
When Hale embarked on the ambitious project of establishing Yerkes Observatory in Wisconsin, a move of considerable scientific significance, he naturally brought Ellerman along with him in 1895 [3] [9]. At Yerkes, Ellerman was noted for his affable nature, integrating smoothly with the local populace. His community engagement was such that in 1899, he was elected clerk of the local county school district [8]:28, a testament to his unassuming charm beyond the confines of a telescope. A significant portion of Ellerman's time at Yerkes was dedicated to extensive observation using the Rumford spectroheliograph [10], an instrument designed to photograph the sun in specific wavelengths of light. Concurrently, he was engaged in the meticulous task of photographing the stellar spectra of what were then classified as Secchi's Fourth Type stars [11] [3]. These intriguing celestial bodies would later be more precisely categorized and understood as carbon stars. In 1900, Ellerman's commitment to solar observation led him to join the American Astronomical Society (AAS) solar eclipse expedition, traveling to Wadesboro, North Carolina [12]. It seems even then, the universe demanded travel, not just quiet contemplation.
Long shed for the Snow Horizontal Telescope
The year 1904 marked a pivotal transition. In March, Ellerman once again accompanied Hale, this time on an expedition to the rugged terrain of Mount Wilson in California. The objective was rather pragmatic: to meticulously assess the viewing conditions and overall suitability of the site for a proposed observatory, an ambitious undertaking slated for financing by the burgeoning Carnegie Institution. The initial and foundational instrument planned for this new high-altitude outpost was to be the Snow Horizontal Telescope, a specialized solar telescope generously funded by Helen Snow of Chicago [13]. This instrument, a testament to both philanthropic vision and engineering ambition, became operational on March 15, 1905. Ellerman, predictably, assumed the critical role of the primary observer, expertly manning the new spectroheliograph [14] [15].
During the observatory's formative years, a period demanding both scientific rigor and sheer perseverance, Ellerman undertook the arduous task of capturing a white-light photograph of the Sun almost daily. This was then followed by subsequent images taken at precise, specific wavelengths, building an invaluable chronological record [7]. His practical skills, honed during his soap-making days and perfected at Yerkes, proved not just useful, but absolutely indispensable at the remote and often challenging mountain site. His talent for equipment repair and, more importantly, ingenious "jury-rigging" (a term that barely captures the art of making do with what one has when far from civilization) kept the delicate instruments functioning [16]. Recognizing this invaluable aptitude, a fully-equipped machine shop was soon thoughtfully added to the Observatory's facilities, expressly for Ellerman's use. Indeed, much of the subsequent, remarkable growth and expansion of the Mount Wilson Observatory itself was meticulously documented through Ellerman's extensive photographic archives, offering a visual history of a scientific frontier [16].
Ellerman's collaborative work with Hale during this period was particularly fruitful, leading to several groundbreaking discoveries in solar physics. Their observations culminated in the identification of solar vortices, swirling patterns that hinted at powerful underlying forces. This, in turn, paved the way for the momentous identification of the magnetic fields within Sun spots in 1908 [3] [17]. Further meticulous work allowed them to discern the polarity of these sunspot magnetic fields, a discovery that ultimately led to the even more profound revelation of the periodic reversal of the magnetic field in these dynamic solar features [3] [17]. In 1910, a brief but significant interlude occurred when Ellerman was granted a leave from the Carnegie Institution. This was for a rather singular, one-man expedition to the remote Hawaiian Islands with the specific, time-sensitive purpose of observing Halley's Comet during its much-anticipated passage [18]. Arriving on March 28, his observation station was strategically established on Diamond Head, Hawaii. He first successfully sighted the comet on April 14, and by the 25th of that month, he was capable of taking detailed observations. Despite persistent challenges from cloud cover and formidable windy conditions, Ellerman managed to capture a total of 73 photographs of the comet across 36 distinct observation dates [19] [20], a testament to his tenacity and photographic skill.
Sunspot illustration by Ellerman, 1917
It was while stationed at the Mount Wilson Solar Observatory in 1915 that Ellerman, with his characteristic observational diligence, meticulously studied an unusual and transient phenomenon. These events were observed at multiple, discrete locations within the lower chromosphere layer of the Sun. They manifested as intensely bright emission features, strikingly visible in the wings of hydrogen-alpha absorption lines [21]. This enigmatic phenomenon later acquired the rather evocative and slightly ominous moniker of Ellerman bombs, primarily because Ellerman noted their distinctly localized nature and their fleeting existence, typically lasting only 10–20 minutes [22]. It should be noted, however, for the sake of historical accuracy (and perhaps to inject a touch of cosmic irony), that while Ellerman extensively studied and characterized this behavior, the initial discovery of these localized brightenings was actually made by W. M. Mitchell in 1900, observed near an active region of the Sun [23]. Ellerman, it seems, was merely the better publicist, or perhaps, the more thorough documentarian.
Ellerman's quiet dedication and scientific contributions were eventually recognized with an honorary MS degree, bestowed upon him by Occidental College on June 20, 1927 [24]. In the spring of 1929, still indispensable, Ellerman accompanied the legendary E. Hubble and M. L. Humason on a series of expeditions. These journeys were undertaken with the critical objective of scouting and identifying a suitable location for the proposed Hale Telescope, an instrument destined to redefine our understanding of the universe. Their travels led them through a hilly region south of Los Angeles and into the vast expanses of Arizona, meticulously checking viewing conditions at each potential site. Ellerman, ever the pragmatist, served as the expedition's mechanic, responsible for the crucial task of setting up the smaller, portable telescopes used for evaluation [25]. His detailed reports and observations from these trips were not merely advisory; they heavily influenced the ultimate selection of the final, iconic site for the Hale Telescope [16], demonstrating that even the most profound scientific leaps rely on reliable infrastructure and the skilled hands that build it.
Ferdinand Ellerman finally retired in 1938 [3], presumably to a life less dictated by the whims of the sun and distant comets. However, the universe, in its usual unsentimental manner, had other plans. During a severe bout of influenza, he tragically succumbed to pneumonia on March 20, 1940, at the Queen of Angels Hospital in Los Angeles, California [1]. He was 70. Despite his relentless work ethic and the often solitary nature of astronomical observation, Ellerman was remembered by his contemporaries as a friendly, jovial, and notably talkative man [8]:28. Beyond the observatory dome, he was an ardent outdoorsman with a keen interest in sports, actively participating in his local community, and frequently delivering engaging lectures on popular astronomy [3], bringing the distant cosmos closer to curious minds.
In a posthumous recognition, perhaps a final, silent nod from the cosmos he so diligently observed, the 46.21 km (28.71 mi) diameter Ellerman crater on the enigmatic far side of the Moon was formally named after him by the International Astronomical Union (IAU) in 1970 [26]. A fitting, if somewhat remote, monument to a man who spent his life illuminating the distant.