Whitepeak Observatory, Tacoma, WA

A Tale of Two Brothers and Their Craters: The story behind the renaming of Crater Pickering, Messier A and of the Pickering brothers


The lunar craters Pickering and Messier A have an interesting and rather uniquely interwoven history. Observers may notice that lunar cartography prior to the mid 1960's listed Messier's companion crater as Pickering, or Wm. Pickering. This official designation was later reversed after this crater pair was recognized as oblique impacts and determined to be physically related. And so, as a result, crater Pickering was re-named back to Messier A to better reflect their physical relationship during the IAU meeting of 1964. At the same meeting they christened another crater near Horrocks (see image for location) in continued honor of William Pickering; Edward Pickering was first officially added as a co-honoree at this time as well. The crater Pickering was originally named in honor of William H. Pickering during the 1935 meeting of the IAU, an especial honor as we shall later see.


(Pickering Crater's present location.)

William Henry Pickering and his older brother Edward Charles Pickering were both notable American astronomers and both were associated with Harvard University virtually their entire professional lives. Both began their careers as instructors in the Physics department at MIT and both were later directors of Harvard Observatory facilities; Edward served as the Director of the principle observatory for over four decades and younger brother William served as the director of several Harvard substation observatories; one in Jamaica, another near Mt. Wilson and another, Boyden Station in Peru. Both were widely esteemed astronomers in their time and both contributed greatly to the science and were widely recognized, contemporaneously, through many awards and honors awarded internationally.

(Edward, MIT archives) (William, unattributed)

One of the truly foresightful actions Edward Pickering is considered responsible for on Harvard's behalf were his utilization and acceptance of women's efforts on the Harvard Observatory department staff at a time when little acceptance or opportunity for women otherwise existed within the field of astronomy. His efforts in mentoring women of his acquaintance he considered promising were widely known at the time--one started out as a maid in his home, Williamina Fleming, who discovered of the Horse Head nebula in 1888! Edward's open-mindedness towards the potential of womankind continued to pay off handsomely--as the accomplishments of other members of "Pickering's Harem" (as they were often lightheartedly called) such as Henrietta Swan Leavitt, Annie Jump Cannon and Antonia Maury can amply attest. An amusing old photo of the enlightened Harvard Observatory staff whooping it up in 1929 is shown below:


(Harvard Observatory archives)

A less kind fate, which we will try to rectify here, is threatening Edward's younger brother's reputation and place in history, William Pickering. Unfortunately, thanks to oddly misleading & inaccurate accounts of William Pickering's life, character and accomplishments widely circulating on the Internet as fact http://physics.ccri.edu/keefe/WHPickering.htm (Example) , added to a distant-in-time third-hand account that alleged Pickering "died a bitter man" and unappreciated by his peers (Sheehan, The Planet Mars) the younger Pickering's reputation is being unjustly tarnished. That such accounts benefit primarily from a lack of appreciation for the times in which this man lived and worked, and rely overly on the arrogance of hindsight in assailing Pickering's ideas as well as misinformation, is self-evident. Such disparaging characterizations as these upon Pickering constitute a tragic defamation of one of America's most notable astronomers and lunar observers.

In point of fact, William Pickering was so well thought of by Harvard that upon his retirement he was awarded Professor Emeritus status and also allowed unfettered & private use of the observatory he established on Harvard's behalf in Jamaica, until the end of his life. William Pickering had many notable accomplishments to his credit: An avid photographer, he created the first usable and complete large photographic atlas of the Moon using the 12" 135foot focal length telescope at Harvard's Jamaica observatory. All areas of the near face of the Moon were covered using five angles of illumination, a technique presaging Kuiper's seminal Consolidated Atlas of the Moon of the early 1960's and Henry Hatfield's famous atlas for amateurs which came out a few years later. William Pickering discovered Phoebe, a moon of Saturn and presaged the existence of both Pluto and Kuiper Belt objects generally long before they were discovered to actually exist. He played a pivotal role in encouraging his brother, as Director of Harvard Observatory, to embark upon assembling the most ambitious and extensive set of stellar photographic plates in existence beginning in the late 19th century (The Harvard College Observatory plate collection). William assembled and headed up the photographic team which began this task in the 1880's, laying the groundwork for a collection of now historic plates that number over half a million. William also helped Percival Lowell select the site on which Lowell observatory was later established and also was the first to suggest Mt. Wilson as the site for the observatory of that name, having earlier established a yet another Harvard substation observing facility nearby. He was the one of the first of the few individuals in history to be accorded the honor of having a lunar crater named for him while still living, awarded by his peers in the IAU in 1935, three years before his death. With these facts in mind it becomes very difficult to credit Sheehan's assertions that "Most professional astronomers paid little attention to Pickering and he died, a bitter man...".

Far from being a 'crackpot' as some internet gadfly's allege, he in fact professionally disassociated himself from Percival Lowell when the latter eventually became infatuated with the idea of intelligent, rather than primitive forms of life on Mars (an idea not wholly dismissed to this day). Pickering's ideas relevant to primitive forms of life upon the Moon as an explanation for anomalous changes in albedo within certain lunar craters as the lunar day progressed may seem outlandish today-- but it should be remembered that as late as the 1960's the possibility of lunar life forms was still taken seriously enough by science to result in establishment of the extensive decontamination and quarantine protocols the first returning Apollo crews were put through upon return from the Moon. Pickering is often derided these enlightened days for his idea that there might possibly be a form of animal life extant upon the Moon--Pickering's migrating Moon bugs. But when we look at his actual papers on the subject, he sounds less the lunatic and more a typical early 20th century scientist instead, inevitably tied to the not-so-advanced state of biological understanding of his day in an attempt to formulate hypotheses to explain anomalous observations of changing lunar albedo:

"A few words may now be said on the chief objection that has been raised to the theory that these changes are due to vegetation, namely the lack of water on the Moon. While it is true that water cannot exist in the free state under a pressure that is less than 4.6 millimetres, and while it is also true that no such pressure apparently exists upon the Moon's surface, still there is nothing to prevent water occurring beneath the surface of the ground, retained by the capillary action of the soil. It has been shown by Cameron that water can be extracted by dry soil from a membrane against a calculated osmotic pressure of 36 atmospheres, or about 500 pounds per square inch. Since on the Earth plants can live on moisture which they have in turn extracted from such a soil, there seems no difficulty in understanding how they could live on the Moon, in a soil which could thus retain considerable moisture in spite of the low atmospheric pressure. Indeed, if it were possible to conceive of an organism which could absorb oxygen directly from vegetation, and store it during the lunar night, there is no reason why animal life should be impossible upon the Moon." --Annals of the Harvard College Observatory Vol. LIII No. IV 1905.

William Pickering was, in fact, one of turn-of-the-century America's preeminent astronomers, respected & oft honored by the various professional societies of his peers during his lifetime, and recipient of many coveted professional honors throughout his lifetime. He further often acted as an especial professional friend to amateur astronomer's worldwide. He and his brother can thus be seen to be quite deserving of the honor represented by their little 15kilometer namesake crater on the Moon, regardless of it's current or past position!.


--Information on William Pickering was based on the notices of the Royal Astronomical Society and the obituary written by Leon Campbell of Harvard Observatory at the time of William Pickering's death as published by the Astronomical Society of the Pacific. Information on Henry Pickering was obtained from the same publications.

W.H Pickering: Royal Astronomy Society Obituary 1939

W.H Pickering: Astronomical Society of the Pacific Obituary 1938

Professor William H. Pickering-An Appreciation; Obituary 1938, Popular Astronomy, Martz, E. P., Jr. (extensive)

Pilgrammage to a tropical observatory, Part I, Popular Astronomy 1937, Martz, E. P., Jr. (account of obbserving trip to Pickering's home, "Woodlawn", near Mandeville)

Pilgrammage to a tropical observatory, Part II

E.C. Pickering: Royal Astronomical Society Obituary 1920

E.C. Pickering: Astronomical Society of the Pacific Obituary 1919

Further fascinating biographical information on the accomplishments of the Pickering brothers (and photos and information on the women of Harvard Observatory) can be found at this address: The Horsehead Project

Further information on the accomplishments of the women of "Pickering's Harem" can be found here: Pickering's Harem, Harvard University


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