|Harold Delos Babcock
US astronomer and
- He measured
the Sun's general magnetic field 1948 and studied the the relationship
between sunspots and local magnetic fields.
- He also did
important work in spectroscopy Babcock was born in Edgerton, Wisconsin,
and studied electrical engineering at the University of California
- In 1909 George
Hale invited him to work at the Mount Wilson Observatory near Los
Angeles, where he remained until 1948, with breaks during the two
- Babcock made
an investigation of the Zeeman effect (whereby a magnetic field causes
a substance's spectral lines to be split) in chromium and vanadium
- important elements in the solar spectrum.
- He then produced
a revised table of wavelengths for the solar spectrum, published 1928
and including 22,000 spectral lines (extended 1947 and 1948).
- It was in collaboration
with his son Horace Welcome Babcock (1912- ) that he succeeded in
measuring the solar magnetic field.
- They used an
instrument of their own design, the 'solar magnometer', which exploited
the Zeeman effect to produce a continuously changing record of the
Sun's local magnetic fields.