A Tale of Two Brothers and Their Craters

The Pickering Brothers – The renaming of Crater Pickering and Messier A

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 the 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 initially named in honor of William H. Pickering during the 1935 meeting of the IAU, a special honor which will later be discussed.

Pickering Crater's location on the surface of the moon.
Pickering Crater’s location on the surface of the moon.

William Pickering and his older brother Edward Pickering were both notable American astronomers and 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 principal observatory for over four decades, and his 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, contributed significantly to the science, and were widely recognized contemporaneously through many awards and honors awarded internationally.

A picture of Edward Pickering.
MIT Archives: Edward Pickering
An image of William Pickering in his middle aged years.
William Pickering

One of the truly foresightful actions Edward Pickering is responsible for on Harvard’s behalf was 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, whom he considered promising, were widely known at the time. One started as a maid in his home, Williamina Fleming, who discovered the Horsehead 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:

An Image of William Pickering and the Harvard Observatory staff performing a theatrical presentation.  Circa: 1880's.
Harvard Observatory Staff

William Pickering, Edward’s younger brother, was so well thought of by Harvard that upon his retirement, he was awarded Professor Emeritus status and allowed unfettered & private use of the observatory 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″ 135-foot 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 1960s and Henry Hatfield’s famous atlas for amateurs, which came out a few years later.

William Pickering discovered Pheobe, a moon of Saturn, and presaged the existence of both Pluto and Kuiper Belt objects long before anyone knew them to exist. He played a pivotal role in encouraging his brother, as Director of Harvard Observatory, to assemble 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 created and headed up the photographic team which began in the 1880s, 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 was the first to suggest Mt. Wilson as the site for the observatory of that name, having earlier established yet another Harvard substation observing facility nearby.

He was 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.

Far from being a ‘crackpot’ as some 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 (a concept 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 be an extant form of animal life 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 is considered one of turn-of-the-century America’s preeminent astronomers, respected & often honored by the various professional societies of his peers and recipient of many coveted professional honors throughout his lifetime.

In addition, he often acted as a remarkable professional friend to amateur astronomers worldwide. Ultimately, he and his brother can be seen as quite deserving of the honor represented by their little 15-kilometer namesake crater on the Moon, regardless of its current or past position.

Written by CityAstronomy.com

We hope you enjoy these articles about space and astronomy.
Let us know if you have any new topics you would like us to cover, and we'll do our best to add them to our future article list.

Sign up for our email notifications to be alerted once new articles are published.

You May Also Like

The article you just read is part of the City Astronomy “Astronomy” collection. If you enjoyed it we think you'll love these other recommendations:

A Gibbous Moon in a dark night sky.

Discover why this lesser known phase called the Gibbous Moon is a great time to observe the lunar surface.

A shooting star racing across the sky at night over a forest canopy

In this article we explain what a Shooting star is and where they come from.

A picture of six images of the Moon in different colors.

Find out what color the Moon REALLY is and why it can look different from night to night.