Speaker
Description
In 1896, Edward Charles Pickering (1846-1919), Director of the Harvard College
Observatory (HCO), reported in a trio of publications the observation of “peculiar
spectra” of the southern star ζ Puppis, which he attributed to an “element not yet
found in other stars or on earth.” Supported by laboratory spectra obtained by Alfred
Fowler (1868-1940), Niels Bohr (1885-1962) showed in 1913 that this “element” was in
fact ionized helium, He+. Its spectrum has become known as the Pickering Series, even
though Pickering credited Williamina Fleming (1857-1911) for the discovery. Fleming
was one of HCO’s “computers” and the future Curator of the Astronomical Photographic
Glass Plate Collection. The series of spectral lines associated with Pickering’s name
played a unique role on the path to quantum mechanics by serving as a proving ground
for Bohr’s model of the atom. Our examination of the discovery of the Pickering series
relied on the records held at the Center for Astrophysics | Harvard & Smithsonian
(the successor institution to HCO), especially the Notebooks and Diaries of Williamina
Fleming and others as well as on the Center’s Glass Plate Collection. Glimpses of the
“peculiar sociology” of a research institution, half of whose staff were women employed
on grossly unequal terms with men, are given in the course of the narrative.
