Annie Cannon

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Biography of Annie Jump Cannon American astronomer pioneer in her profession. Her work on star cataloging has been central to the current stellar classification.

Annie Cannon’s family and early life

Annie Jump Cannon was born on December 11, 1863 in Dover, a small town that is the capital of the state of Delaware, on the East Coast of the United States.

Her mother’s name was Mary Jump, and she was the one who sparked in Annie a taste for astronomy, stimulating her imagination and curiosity, while showing her the constellations in the night sky.

Annie’s father, Mr. Cannon, was a senator and boat builder in Delaware.

Annie Cannon attended Wellesley College, where she studied physics and astronomy. There she learned to interpret the information obtained with a spectroscope.

Dover Delaware
The city of Dover founded in 1683 is located in the center of the state of Delaware. Credit: Wikipedia.

At age 17, in 1880, Annie Cannon enrolled at Wellesley College, a private women’s university that had opened its doors in 1875.

This university is in the city of Wellesley (in the state of Massachusetts), on the east coast of the USA, 21 km from Boston.

The founders of this college wanted to provide an excellent liberal education for women. Their motto is the biblical quote “I have not come to be served, but to serve“.

At this university, Annie learned Newtonian mechanics, calculus, biology, and astronomy.

Among her teachers, Annie Cannon was fortunate to have Sarah Whiting, hired as a physicist in 1875. Sarah had formed the experimental physics department at Wellesley.

On the director’s advice, Sara Whiting attended Charles Pickering’s lectures at MIT. Professor Pickering invited Sarah to look at some of the new techniques being applied to astronomy.

In 1880 Sarah Whiting began teaching an Applied Astronomy course at Wellesley College.

Annie Cannon traveled Europe

Four years later, in 1884, and with a degree in physics, Annie Cannon decided to embark on an adventure through Europe, where she developed her taste for photography, a very novel art at that time.

On this trip through Europe, she dedicated herself to observing the sky from that other region of the world. She photographed the various constellations and created an extensive catalog of images.

While in Spain, she had the opportunity to witness and photograph an eclipse of the Sun.

When she returned to Dover, Annie noted that her mother was becoming increasingly frail. She decided to take care of her personally during her last years of life.

Annie spent her free hours studying astronomy, which had become a real passion for her.

Annie Cannon’s working life

After her mother’s death in 1894, Annie called Sarah Whiting, her former Massachusetts teacher, to ask her to get her a job as a physics teacher.

Sarah Whiting remembered her fondly and Annie was immediately hired as a junior physics teacher.

Seeing Annie Cannon’s impressive intelligence, and interest in astronomy, her superiors sent her to study astronomy at Radcliffe College. This women’s university is located in Cambridge (Massachusetts) and was attached to Harvard University.

There she received classes from Charles Pickering, one of the most important scientists of the time, and director in those years of the Harvard Astronomical Observatory.

Charles Pickering
Edward Charles Pickering astronomer, discoverer of stars and the worth of women. Credit: Popular Science Monthly

In 1886, Charles Pickering had formed a group of talented women to engage in photographic analysis of stars and the classification of spectra on photographic plates.

To this select group, called “Harvard Computers” belonged Williamina Fleming, who had started out as a servant at Charles Pickering’s house.

Edward Pickering hired Annie Cannon as an “assistant” to the Harvard Observatory. In 1896 Annie became one of the women who made up the Harvard Computer team.

Annie Cannon was tasked with continuing to rank stellar in the Southern Hemisphere.

She developed various improvements to the Pickering cataloging system.

She found a simple and creative method to streamline work. She established classification rules, based on the temperature of the stars, and made substantial progress in spectral classification.

Annie Cannon developed the Harvard Classification Scheme, which is the foundation of the currently used system.

Cecilia Payne-Gaposchkin was one of her first collaborators.

Another of Annie Cannon’s companions was Antonia Maury. This clever woman came up with a method to describe the relative size of stars according to their spectrum. In 1901, she completed her own stellar classification.

She was also the companion of Annie Cannon Henrietta Swan Leavitt, who observing the stars in the Magellanic Cloud, came to the discovery of the “Cepheids” and a modern understanding of the size of the universe. Their contributions continue to be the essential tool for measuring cosmological distances.

As a result of the work of the “Harvard Computers“, Pickering published the first Henry Draper Catalog in 1890, with more than 10,000 stars classified according to their spectrum.

While some of the women on Pickering’s staff were graduates in astronomy, their salary was similar to that of an unskilled male worker. They earned more than a woman working in a factory, but less than an office worker.

AstrĂ³nomas de Harvard
Edward Pickering and his team of calculators outside the C building of Harvard College. Credit: Wikipedia.

Annie Cannon did such an amazingly wonderful job that Charles Pickering proposed to the President of Harvard University that she be given an official appointment.

Unfortunately, the President, surnamed Lowell, only authorized Pickering to offer Annie Cannon a “conservative astronomical photography” position. Nor did the university president authorize the name Cannon to appear as a co-author of the Harvard Observatory’s catalog of stars.

She was only appointed as a regular professor of astronomy in 1938.

Despite Pickering’s strong support, all of her knowledge, and her valuable discoveries, Annie Cannon never got promoted to “astronomer” at the Harvard Observatory.

But she never gave up and kept working until she rated more than 225,000 stars.

Annie Cannon en 1992
Portrait of Annie Cannon in 1922, at age 59. Credit: Wikipedia

Last years in the life of Annie Cannon

In 1901, Annie Cannon published her first stellar catalog. That was the beginning of a stage in which she dedicated her life to writing books, participating in conferences and promoting meetings of women scientists.

In those years there was no internet. Had it existed, Annie Cannon would have been one of the most fruitful promoters of blogs dedicated to visualizing the work of women.

Little by little, her name and the important result of her classification reached academic and scientific circles.

The Harvard spectral classification is now recognized as her invention, and in 1922 the International Astronomical Union adopted the stellar classification system devised by Annie Cannon.

Annie retired from the Harvard Observatory in 1940, but continued the investigation until her death.

She died on April 13, 1941 in Cambridge, Massachusetts.

Main recognitions

  • Annie Cannon received an “Honorary Doctorate” from the University of Groningen in the Netherlands (1921).
  • In 1923, she was elected one of the twelve most important living American women.
  • She was the first female astronomer to receive an honorary doctorate from the University of Oxford (1925).
  • Annie Cannon is the first woman elected as an officer of the American Astronomical Society.
  • In 1931, she was the first woman to receive the Henry Draper Medal, awarded by the National Academy of Sciences.
  • In 1933, the American Astronomical Society established the Annie Cannon Award.
  • She was appointed Member of the Royal Astronomical Society, London.
  • The lunar crater Cannon is named after her.
  • The asteroid (1120) Cannonia is named after her.

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