Sky & Telescope - June 2024 - 33

in October 1959, but his travels had taken a
physical toll. His hip had grown worse with
age, and now he suffered from spinal bone
spurs that, by January 1960, required surgery.
During a slow convalescence, he suddenly
collapsed and died in June of that year.
It now fell to others to finish analyzing
Baade's considerable backlog of documents.
Henrietta Swope, his longtime assistant and
collaborator, continued the job of processing
the piles of photographs and data, listing
Baade as co-author on all resulting articles.
Cecilia Payne-Gaposchkin, the Harvard astrophysicist
whose findings revolutionized our understanding of stellar
composition, had arranged Baade's post-retirement visit. In
addition, she converted his lecture notes into the book Evolution
of Stars and Galaxies, which Harvard University Press
published in 1963, with Baade listed as the primary author.
Walter Baade may not be as well-known as some other
astronomers, but his legacy is as profound as that of any of
his contemporaries. Today's astronomers still continue along
the scientific paths he established, refining calculations of
galactic distances and the age of the universe using Cepheid
variables and supernovae. Among them is Wendy Freedman
(University of Chicago and former Director of the Carnegie
Observatories). " It's not quite fair to say he single-handedly
came on to this idea of [stellar] evolution, " she says about
Baade's legacy. " But he significantly broadened our thinking
by showing, through differences in star populations between
COLLEAGUE AND COAUTHOR Cecilia PayneGaposchkin
was a British-born astronomer who
studied under Shapley. The first person to earn a
doctorate at Radcliffe College (in Cambridge, Massachusetts),
she performed pioneering research into
the chemical processes of stars and on the nature
of variable stars. It was Payne-Gaposchkin, an admirer
of Baade's, who collected and edited his notes
after his death.
elliptical and spiral galaxies, that there were
different routes to evolution.
" He enabled people to ask more detailed
questions about how galaxies change with
time, " she adds, " and inspired countless young astronomers
to flesh out these areas with new ideas and data. "
Baade wanted to establish a Southern Hemisphere observatory
as far back as 1927, but he never realized his dream.
He tried to observe the southern sky from Argentina during
World War II but was barred from traveling there because of
his citizenship. And although his lifelong advocacy eventually
helped establish the European Southern Observatory, he
never worked in that part of the world. In 2000, however, the
256-inch (6.5-meter) Walter Baade Telescope began operating
at Las Campanas Observatory in Chile, where it will gather
data from the southern sky for decades to come.
¢ STEVE MURRAY is a freelance science and technology
writer who stargazes from his home in San Diego, California.
He also provides STEM presentations to a variety of audiences
as a NASA/JPL Solar System Ambassador.
THE SEARCH GOES ON Twin 6.5-meter Magellan Telescopes scan the skies from Las Campanas Observatory, located in the Atacama
Desert of Chile at an altitude of nearly 2,400 meters (8,000 feet). The Walter Baade Telescope (on the left) was the first of the two instruments
to be completed and saw first light in 2000.
sk yand tele scope .o r g * JUNE 2024 33
PAYNE-GAPOSCHKIN: SMITHSONIAN INSTITUTION / WIKIMEDIA COMMONS
/ PUBLIC DOMAIN; ESO WALTER BAADE TELESCOPE: JAN SKOWRON /
WIKIMEDIA COMMONS / CC BY-SA 3.0

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Sky & Telescope - June 2024

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