In astronomy, stellar classification is governed by
the Morgan-Keenen system, which categorizes stars
based on their composition and surface temperature. The
origins of this system can be traced back to the work of
Annie Jump Cannon, a late nineteenth-century and early
twentieth-century 1 astronomer. Spending over forty
years classifying stars based on their unique spectra of
transmitted light.
[1] Beginning early in her life, Cannon demonstrated
an exceptional aptitude for the physical sciences. [2]
Later, as a student at Wellesley College, Cannon earned a
degree in physics and became an expert in spectroscopy:
the process by which light is separated into its component
wavelengths. [3] During this period, she also took
up photography and traveled extensively in order to
experiment with the newly invented black-box camera.
[4] As a child, she developed an interest in astronomy and
purportedly used her attic as a makeshift observatory. 2
Cannon’s background in physics, astronomy, and
photography provided her with a unique skillset that 3
will serve her well for the rest of her career. After working
as a research assistant for a number of astronomers at
Wellesley and Radcliffe Colleges, Cannon was hired
by Professor Edward Charles Pickering, the director of
the Harvard College Observatory. Under Pickering, she
classified over 300,000 stars—more than any other human
in history—using only a telescope, a spectrometer, and
a camera. Using this knowledge, she developed her own
classification system that relied on the surface temperature
of the stars, which could be approximated using the
spectrum of light transmitted from each star. It was said
that Cannon could classify three stars a minute and, using
a magnifying glass, could classify stars down to the 9th
magnitude-sixteen times fainter than 4 humans.
Today, Cannon’s unique classification system is used
by countless astronomy enthusiasts around the world.
5 Pickering was succeeded by Harlow Shapley. Shapley
once said that Cannon’s contribution to astronomy was “a
structure that probably will never be duplicated in kind or
extent by a single individual.” Indeed, Cannon’s work has
forever shaped our comprehension and perception of the
vast and elaborate universe.
the Morgan-Keenen system, which categorizes stars
based on their composition and surface temperature. The
origins of this system can be traced back to the work of
Annie Jump Cannon, a late nineteenth-century and early
twentieth-century 1 astronomer. Spending over forty
years classifying stars based on their unique spectra of
transmitted light.
[1] Beginning early in her life, Cannon demonstrated
an exceptional aptitude for the physical sciences. [2]
Later, as a student at Wellesley College, Cannon earned a
degree in physics and became an expert in spectroscopy:
the process by which light is separated into its component
wavelengths. [3] During this period, she also took
up photography and traveled extensively in order to
experiment with the newly invented black-box camera.
[4] As a child, she developed an interest in astronomy and
purportedly used her attic as a makeshift observatory. 2
Cannon’s background in physics, astronomy, and
photography provided her with a unique skillset that 3
will serve her well for the rest of her career. After working
as a research assistant for a number of astronomers at
Wellesley and Radcliffe Colleges, Cannon was hired
by Professor Edward Charles Pickering, the director of
the Harvard College Observatory. Under Pickering, she
classified over 300,000 stars—more than any other human
in history—using only a telescope, a spectrometer, and
a camera. Using this knowledge, she developed her own
classification system that relied on the surface temperature
of the stars, which could be approximated using the
spectrum of light transmitted from each star. It was said
that Cannon could classify three stars a minute and, using
a magnifying glass, could classify stars down to the 9th
magnitude-sixteen times fainter than 4 humans.
Today, Cannon’s unique classification system is used
by countless astronomy enthusiasts around the world.
5 Pickering was succeeded by Harlow Shapley. Shapley
once said that Cannon’s contribution to astronomy was “a
structure that probably will never be duplicated in kind or
extent by a single individual.” Indeed, Cannon’s work has
forever shaped our comprehension and perception of the
vast and elaborate universe.