Vera C Rubin

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Journal of Astronomical History and Heritage, 13(2), 145-148 (2010). 
 
145 
CHARLOTTE MOORE SITTERLY 
 
Vera C. Rubin 
Department of Terrestrial Magnetism, Carnegie Institution of  
Washington, Washington, DC, USA. 
E-mail: vrubin@ciw.edu 
 
Abstract: Charlotte Moore Sitterly was a scientist in an era when it was rare for a woman to have the opportunity to 
devote her life to forefront science.  Following her graduation from Swarthmore College in 1920, she accepted a 
position at Princeton University as an assistant to Henry Norris Russell.  In 1925 she started a study of the solar 
spectrum.  She could then not know that she would devote much of her scientific career to gathering basic atomic 
data that are invaluable to the scientific community, even today.  In 1931 she obtained a Ph.D. degree at the 
University of California, Berkeley, and returned to Princeton as a staff member of the Princeton University Observa-
tory.  In 1945 Moore moved to the National Bureau of Standards (NBS), to supervise preparation of the widely-used 
tables of atomic energy levels.  Following the successful launching (1946) of a V2 rocket to obtain the ultraviolet 
spectrum of the Sun, she started working also with Richard Tousey and his group at the Naval Research Laboratory 
(NRL).  Ultimately, they extended the solar spectrum down to 2200 angstroms.  She continued her affiliations with 
both the NBS and the NRL until her death in 1990.  Charlotte Moore was a rare scientist who devoted her career to 
obtaining accurate numbers, thus enabling the scientific community to open her tables and know that the data are 
reliable.  
 
Keywords: Sitterly, Moore, multiplet tables. 
 
1  INTRODUCTION 
 
Charlotte Moore (Figure 1) was born in 1898 in Ercil-
doun, a country village in Chester County, Pennsyl-
vania.  This was an auspicious time to be born for one 
who would spend her adult life insuring that spectro-
scopists would have access to accurate wavelengths.  
One year before her birth, Henry A. Rowland, Johns 
Hopkins University’s first Professor of Physics, com-
pleted publication of 20,000 lines in the solar spec-
trum.  These would become part of Charlotte Moore’s 
library, and today astronomers still use Rowland-style 
gratings.  One year after her birth, Lewis E. Jewell of 
Johns Hopkins defended his (Jewell’s) measurements 
of Hδ in the solar spectrum.  It was Jewell who 
measured and calculated the values published in Row-
land’s tables.  In that same year, 1899, Julius Scheiner, 
at the Potsdam Observatory, published the first-known 
spectrum of the Andromeda Galaxy, and announced 
that it was composed of stars like the Sun.  Charlotte 
was two years old when Samuel P. Langley extended 
the solar spectrum still farther into the infrared (see 
Figure 2).  Charlotte was 16 years old when Bohr ad-
vanced his model of the hydrogen atom. 
 
Charlotte’s parents had no college degrees, but they 
were teachers who taught in an ‘old style’ (her term) 
academy and later became interested in public school 
education.  They worked in the education system of 
Chester County for many years, and her father became 
Superintendent of Public Schools.  Her parents were 
strict about learning, especially grammar.  Charlotte 
was the youngest in a family of three daughters and 
one son.  They all attended public schools. 
 
Because of their Friends (Quaker) background, her 
parents chose Swarthmore College for Charlotte, who 
apparently had little choice in the decision.  When 
interviewed by David DeVorkin in 1978 (Sitterly, 
1978), Moore said: 
 
We were not well off financially.  I had to do a lot of 
extra work to get through college.  I used to do sub-
stitute teaching because it paid well.  Substitute teach-
ing and tutoring were the two fields in which a woman 
could get some money toward working her way through 
college; almost everything else favored the men.  I 
taught every grade from first grade up to senior high 
school. 
 
Moore’s attitude toward college was to learn as much 
as possible in various fields.  Ultimately she majored 
in mathematics, and took an astronomy course using 
Forest Ray Moulton’s general astronomy text.  She 
graduated in 1920, but failed to get the graduate 
fellowship that she applied for.  Her advisor, John A. 
Miller, surely recognized her as an unusual student, 
when he suggested that she consider taking a job with 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 1: Charlotte Emma Moore Sitterly, 1898–1990 (court-
esy: National Institute of Standards and Technology). 
Vera C. Rubin                          Charlotte Moore Sitterly 
 
146 
Henry Norris Russell at Princeton.  She neither made 
an application nor met Russell in advance, but the job 
was hers.  Her brilliance was evident even then. 
 
In those years, Russell was devoting his time to 
problems of spectroscopy, chemical abundances, and 
stellar evolution.  When Charlotte joined him at 
Princeton, she was his only assistant, although the 
work he needed done would have taxed several.  Her 
office was located in an old back room over the 
furnace, from which she breathed coal fumes all the 
time.  As Russell’s ‘assistant’ she supplied Russell 
with whatever materials he needed, and he usually 
needed them in a hurry.  She got to know Russell’s 
graduate students, Donald Menzel, Theodore Dunham, 
and Bancroft Sitterly, among others.  She would marry 
Bancroft over a decade later. 
 
Nancy Roman (1991: 1492) has written: 
 
Russell was a quick and brilliant thinker.  Although he 
did tell Charlotte how to do the various things he want-
ed done, his explanations were quick, leaving her to fill 
in the details and all of the background.  
 
Her first job was to determine an accurate position of 
the Moon from photographic plates, a procedure that 
Charlotte described as ‘terribly involved’.  Shortly 
after, she was working on double stars and a “… 
wealth of spectroscopic material.” (Sitterley, 1978)  
She attended some of Russell’s evening graduate 
school lectures, and within five years she was the first 
author on a Moore-Russell publication (Moore and 
Russell, 1926). 
 
She was also exhausted.  So in 1925 she asked Rus-
sell for leave to work at Mt. Wilson, to help with the 
revision of the Rowland Astronomical Tables (St. 
John, et al, 1928).  She worked mostly with Charles St. 
John, and was called a computer, as were all the 
women working there.  She considered this an insult.  
She remained in touch with Russell, and saw him each 
summer when he spent one month at Mt. Wilson.  
Charlotte returned to Princeton in 1928, continuing the 
spectroscopic work.  In 1931 she earned her Ph.D. 
from the University of California at Berkeley, after 
two years of graduate study while Russell was away in 
Europe.  The first year she took courses at Berkeley, 
but she spent the second year at Mt. Wilson Obser-
vatory offices in Pasadena analyzing sunspot spectra.  
Princeton’s graduate school would open to special 
women only in 1961. 
 
 
Although she could have accepted other positions, 
Charlotte returned to Princeton in 1931, and Russell 
offered her a Research Assistantship.  In 1936, she 
became a Research Associate.  In 1937, she married 
Bancroft Sitterly, the graduate student she had known 
since their Princeton days in the early 1920s.  She 
continued to gather data for Russell, and he continued 
to ask her for “…his colossal jobs.  He never asked for 
small ones.  He thought I over stressed (accuracy), but 
I would never give him a list that I wouldn’t stand in 
back of.” (Sitterly, 1978).  Perhaps due to her Quaker 
upbringing and to her parents’ examples, Charlotte 
may have recognized that her major role in science 
could be to make accurate wavelength values available 
to the scientific community.  But regardless of her in-
tentions, she is remembered best for the several edi-
tions of her monumental work, A Multiplet Table of 
Astrophysical Interest (Moore, 1933, 1945, reprints in 
1959 and 1972; Figure 3).  Even today, these pub-
lications identify her as an important scientist. 
 
In 1945, Russell was failing, and Charlotte moved to 
the US National Bureau of Standards.  She continued 
some work with Russell, but she intended to complete 
her work on the infrared solar spectrum with Harold 
Babcock.  Edward Condon, the Bureau Director, want-
ed a complete project on atomic energy levels, which 
was an enormous undertaking. 
 
However, for Charlotte, there were thrills yet to 
come.  In 1946, the Naval Research Laboratory (NRL) 
launched an XUV rocket and obtained its first suc-
cessful rocket solar spectrum.  Charlotte was so excit-
ed that she called Richard Tousey, whom she did not 
know, to congratulate him on the success.  She re-
called a day long ago in Princeton, when she and 
Russell and others were discussing what the ultraviolet 
solar spectrum would look like.  They had fun gues-
sing, but concluded that they would never live to see 
it, because no one could build a spectrograph stable 
enough. 
 
At the Bureau of Standards, the Atomic Energy 
Levels Program was Charlotte’s full time work, and 
the XUV program had to be fitted in when possible.  
But it did become a large part of her interest.  In later 
years she divided her time between the Bureau of 
Standards and the NRL.  She continued gathering data 
and organizing tables of atomic spectra long after 
retirement age, publishing her last collection (Moore, 
1985) shortly before her 87th birthday. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 2: The infra-red solar spectrum of a 60 deg rock-salt prism. From bolographic observations of 1897-1898 (after Langley, 
1900: Plate 20). 
Vera C. Rubin                          Charlotte Moore Sitterly 
 
147 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3: The title page of the 1959 revised edition of the Multiplet Table (Moore, 1959). 
 
 
The scientific community recognized that her work 
was a gift to all, and Moore was awarded numerous 
prizes.  In 1937 she received the second Annie Jump 
Cannon Award of the American Astronomical Society, 
an award that is reserved for women.  But her highest 
honors came much later: the William F. Meggers 
Award of the Optical Society of America, for out-
standing work in spectroscopy, in 1972, and the Cath-
erine Wolfe Bruce Gold Medal of the Astronomical 
Society of the Pacific, for lifetime achievement, in 
Vera C. Rubin                          Charlotte Moore Sitterly 
 
148 
1990.  She was notified of the latter award, but died 
before it could be formally presented to her. 
 
For more details of Charlotte’s life, I highly recom-
mend the extensive and interesting interview that 
David DeVorkin recorded in 1978 (Sitterly, 1978).  It 
is clear from Charlotte’s first words that she is a ‘take 
charge’ person.  In the interview, she said: “My own 
library was not very extensive until my husband sup-
plemented it with his good books.”  To this, David, 
who surely intended to start from the beginning, re-
plied, “Yes, we’ll talk about that later.  Dr. Sitterly, I 
know that you were born in 1898 in Ercildoun”, and 
they went on from there.  Of the many articles follow-
ing her death in 1990, the one written by Nancy 
Roman (1991) for the Bulletin of the American Astro-
nomical Society is especially sensitive and interesting. 
 
2  PERSONAL CONTACT 
 
I will conclude this brief account of Charlotte Moore 
Sitterly’s life with a few personal comments.  I no 
longer remember when and where I met Dr Sitterly.  In 
her conversation with DeVorkin, she describes phon-
ing Dr Tousey at the Naval Research Lab after the first 
successful rocket (X1JV) ultraviolet spectrum of the 
Sun had been safely returned in 1946 (Baum, et al, 
1946).  I worked in Dr Tousey’s division as a summer 
student in 1947 and 1948, and my first project was to 
determine the optical properties of the spherical glass 
bead that was the detector for the rocket flight.  I do 
not remember whether I met Charlotte during that 
time.  I do remember that I periodically went with 
other scientists (all male) to the Naval Station in south-
ern Maryland where the rockets were launched.  I also 
remember that there was no ladies room on the base, 
so I had to use the Captain’s bathroom.  I suppose that 
Charlotte did also. 
 
In 1952 I returned to Washington with a husband, an 
infant, and a Master’s degree in astronomy, having 
studied physics under Richard Feynman, Philip Mor-
rison, and Hans Bethe at Cornell University while my 
husband, Bob, was completing his Ph.D. there.  I en-
tered the Georgetown University graduate school in 
astronomy, the only astronomy graduate program in 
Washington, and took a wonderful course in spectro-
scopy with Carl C. Kiess, of the National Bureau of 
Standards.  He tried to interest me in looking for and 
classifying the weak lines in the solar spectrum for my 
doctoral thesis, but I was interested in galaxies.  I 
chose to write my thesis under George Gamow, who 
was then in the George Washington University Physics 
Department, but my Ph.D. degree is from Georgetown 
University, and it is in astronomy. 
 
In my graduate student years there were few wo-
men astronomers in Washington.  I took advantage of 
Charlotte’s friendliness and her willingness to discuss 
astronomy and spectroscopy with a young student.  
Periodically I would visit her at the Bureau of Stan-
dards (now NIST) to discuss spectroscopy and astron-
omy.  I started measuring spectra for her, using a mea-
suring machine at Georgetown University that could 
accommodate her enormously-large solar plates from 
Mt. Wilson.  They were too large for the Bureau of 
Standards measuring machinery.  I continued visiting 
her over many years, talking spectroscopy, and being 
introduced to many of the Bureau of Standards 
spectroscopists and visitors.  Occasionally Bob and I 
would drive her to lectures of interest.  She was a 
brilliant scientist, a lovely lady, and a delight to know.  
 
3  ACKNOWLEDGMENTS 
 
This paper is based on a talk given in a special session 
on “The First Century of Astronomical Spectroscopy” 
at a meeting of the Historical Astronomy Division of 
the American Astronomical Society on 3 January 
2010.  The session was organized by Joseph S. Tenn 
of Sonoma State University.  
 
4  REFERENCES 
 
Baum, W.A., Johnson, F.S., Oberly, J.J., Rockwood, C.C., 
Strain, C.V., and Tousey, R., 1946. Solar ultraviolet spec-
trum to 88 kilometers. Physical Review, 70, 781-782. 
Langley, S.P., 1900. Annals of the Astrophysical Observa-
tory of the Smithsonian Institution, Volume I. Washington, 
U.S. Government Printing Office. 
Moore, C.E., 1933. A Multiplet Table of Astrophysical Inter-
est. Princeton University Observatory and the Mount Wil-
son Observatory of the Carnegie Institution of Washing-
ton. 
Moore, C.E., 1945. A Multiplet Table of Astrophysical Inter-
est, revised edition. Contributions of the Princeton Uni-
versity Observatory, No. 20. 
Moore, C.E., 1959. A Multiplet Table of Astrophysical Inter- 
est, revised edition. Washington, National Bureau of 
Standards, Technical Note No. 36. 
Moore, C.E., 1985. Selected Tables of Atomic Spectra. 
Atomic Energy Levels, 2nd ed., Multiplet Table and O III. 
Data Derived from the Analyses of Optical Spectra. 
Gaithersburg, MD, USA, National Bureau of Standards. 
Available at http://www.nist.gov/srd/nsrds/NSRDS-NBS-
3-11.pdf. 
Moore, C.E., and Russell, H.N., 1926. On the winged lines 
in the solar spectrum. Astrophysical Journal, 63, 1-12. 
Roman, N.G., 1991. Charlotte Moore Sitterly. Bulletin of the 
American Astronomical Society, 23, 1492-1494. 
Sitterly, C.M., 1978. Interview of Charlotte Moore Sitterly 
by David DeVorkin on 15 June 1978, Niels Bohr Library 
& Archives, American Institute of Physics, College Park, 
MD, USA. Transcript is available at http://www.aip.org/ 
history/ohilist/4784.html.  
St. John, C.E., Moore, C.E., and Ware, L.M., 1928. Revision 
of Rowland’s Preliminary Table of Solar Spectrum Wave-
lengths: with an Extension to the Present Limit of the 
Infrared. Washington, Carnegie Institution of Washing-
ton. Publication No. 396; Mount Wilson Observatory. 
Papers, v. 3. 
 
 
Vera Rubin is an astronomer at the Department of 
Terrestrial Magnetism of the Carnegie Institution of 
Washington in Washington, DC, USA.  She is best 
known for her work on the rotation curves of 
galaxies, which convinced most astronomers that 
the galaxies contain vast amounts of dark matter.  
She has been awarded many honors, including 
the Gold Medal of the Royal Astronomical Society, 
the Henry Norris Russell Lectureship of the 
American Astronomical Society, the Catherine 
Wolfe Bruce Gold Medal of the Astronomical 
Society of the Pacific, the Cosmology Prize of the 
Peter Gruber Foundation and the U.S. National 
Medal of Science. 
 


CHARLOTTE MOORE SITTERLY

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CHARLOTTE MOORE SITTERLY

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