The Astronomy Book

121

See also: The sun’s spectrum 112 ■ The characteristics of stars 122–27 ■
Classifying star spectra 128 ■ Measuring the universe 130–37

THE RISE OF ASTROPHYSICS

the naked eye as a means of
comparing one star’s brightness
with that of another. The wedge
photometer was much more
objective; the observer viewed
a target star alongside one of
several stars with an accepted
brightness and then edged a
wedge of calcite in front of the
known source, diminishing its
magnitude in increments until
the two sources looked to have
the same brightness.
In 1886, Mary Draper, the
widow of spectral photography
pioneer Henry Draper, agreed
to fund Pickering’s work in her
husband’s name. In 1890, the first
Draper Catalogue of Stellar Spectra
was published. Pickering then
opened an observatory in Arequipa,

I do not know if God

is a mathematician,

but mathematics is the

loom on which God

weaves the universe.

Edward C. Pickering Edward C. Pickering

Edward C. Pickering was the

dominant figure of American

astronomy at the turn of the

20th century. Many of the

first steps in the development

of today’s astrophysics and

cosmology were made by

people he employed at the

Harvard College Observatory.

Known as a progressive for

his attitudes to the education

of women and their role in

research, Pickering nonetheless

asserted a rigid authority

over his team. On more than

one occasion, he forced out

researchers with whom he

did not agree, only for them

later to be proved right; one

example of this is Antonia

Maury, whose work on stellar

spectra Pickering dismissed.

Pickering spent his whole

career in academia, but was

also an avid outdoorsman, and

was a founding member of the

Appalachian Mountain Club.

The club became a leading

voice in the movement to

preserve wilderness areas.

Key works

1886 An Investigation in

Stellar Photography

1890 Draper Catalogue of

Stellar Spectra

1918 Henry Draper Catalogue

Peru, to survey the southern

sky and produce the first all-sky

photographic map.

In combination with the

work of the Harvard computers,

Pickering’s data was the basis

for the Henry Draper Catalogue

published in 1918, which contained

spectral classifications for 225,300

stars across the entire sky. ■

Many of the Harvard computers
were trained in astronomy, but as
women, they were excluded from
academic positions. Their wages were
similar to those of unskilled workers.