It was with Mary's encouragement of the subject that Annie would, in the attic of their house using an old astronomy textbook, learn the constellations and identify stars. It would not be until 1898 that she would discover her first star, and confirmation of it would not come until 1905. It was also from her mother that Annie learnt household economics, something she would later put to use in the organisation of her research.
As a student from 1877 to 1880 at Wilmington Conference Academy (now Wesley College) in Dover, Delaware, she showed promise, especially in mathematics. One of the first to enrol, from 1880 Annie attended Wellesley College in Massachusetts, one of the top academic schools for women at the time. Cecilia Payne-Gaposchkin writes :-
Not long ago she was recalling those early days [at Wellesley College], "One might have expected the girls to be very serious and earnest," she said, "but they always seemed to be laughing." And in that spirit she went through life, always endowing what seemed to many people to be an impossibly laborious and exacting occupation with joy and vitality.She graduated in 1884 as the valedictorian with a degree in physics. Following the completion of her degree, she returned to Delaware for the following decade.
It was during this time that she developed her interest and skill at photography. She sailed to Spain in 1892 and there took photographs with her Kameret camera. For the 1893 Chicago World's Columbian Exposition, her photographic work was published alongside her own prose in a pamphlet titled In the footsteps of Columbus. Here is an extract from the pamphlet to illustrate Cannon's prose:-
O Espana, home of the Cid, of Isabella the Catholic, of Columbus, thou hast charms no other land possesses! Thy Castilian valleys weave poetry into the plainest soul. Thy Andalusian mountains breathe romance and song into the very spirit. I am not an artist, but thy splendid sun has painted on my Blair films scenes more truthful than brush or pencil could portray, I am not a poet, but my Kamaret photographs sing thy praise better than song or sonnet.For a longer extract from the pamphlet, see THIS LINK.
It was not long after this that she was rendered almost deaf by a bout of scarlet fever. It was this disability that potentially held her career back in some areas, but may also have helped her in the long-run. It is believed that Raymond Pearl of John Hopkins would not vote her in as a member of the National Academy of Sciences on account of her being deaf. Thus a female astronomer was not elected to the Academy until 1978. However, it is also thought that her deafness made it hard for her to socialise, leading her to a lifestyle whereby she could immerse herself in her work.
She neither married nor had any children. She credited her success to hard work and a lack of distractions :-
I deserve no particular credit; I have concentrated on my work - that is all. I find it so fascinating and absorbing that nothing else exists. The trouble with most women is they do not stick to their work. They marry and drop it. Mind, I believe marriage is a fine thing, if a woman marries the right man. But it should not stop a woman's work any more than it does a man's.With the death of her mother in 1893, life grew more difficult at home. Annie returned to Wellesley for graduate study in mathematics, physics and astronomy. Under the guidance of Professor Sarah Frances Whiting (1847-1927), one of the few female physicists in the United States at the time, Annie gained an interest in the spectroscopic analysis of light. It was with this subject that she would spend the rest of her life.
Electromagnetic radiation from a star is analysed by passing it through a prism or diffraction grating. It displays the rainbow of colours divided by spectral lines, each line indicating a particular chemical element. It is the strength of the line that dictates the abundance of that element in the star.
To advance her work, and access a better telescope, Cannon enrolled at Radcliffe College in Cambridge, Massachusetts as a 'special student'. Radcliffe was set up near Harvard College in order to allow the Radcliffe women to benefit from the addresses given by the Harvard professors, who would go over and repeat their lectures.
Following her studies at Radcliffe, she was hired as an assistant to Edward C Pickering (1846-1919), the newly elected director of the Harvard College Observatory. He had put Williamina P Fleming (1857-1911) in charge of hiring a staff of female assistants, so-called "Pickering's Women". She added Annie to the team in 1896. Between 1885 and 1900, Fleming selected 20 assistants to sort through photographs of stellar spectra. The Second Catalogue of Variable Stars was produced by Annie Cannon and published in 1907 in the Annals of the Astronomical Observatory at Harvard College as Volume 55 Part I. It states on the title page that it is "by Annie J Cannon, Assistant in the Observatory, under the direction of Edward C Pickering, Director of the Observatory." For the Preface written by Edward Pickering, and an Extract of the Introduction by Annie Cannon, see THIS LINK.
Annie and her work were highly praised by Pickering (quoted by many sources, for example ):-
Miss Cannon is the only person in the world - man or woman - who can do this work so quickly.When she first started classifying stellar spectra, she could classify 1000 stars in three years, but by 1913, she was working on 200 an hour. The job at hand was to complete the Henry Draper Catalogue which had been started in 1885. The Catalogue eventually gave spectroscopic classifications of 225,300 stars and was published between 1918 and 1924. The goal was to map and define every star in the sky to a photographic magnitude of about 9. In the first volume, published in 1918, Pickering wrote:-
The classification of the spectra required for the Henry Draper Catalogue was begun by Miss Annie J Cannon on October 2, 1911, and practically completed September 30, 1915. Some additional spectra were taken from later plates, where faint stars had not been classified previously. The total number of spectra classified is 242,093, relating to about 222,000 stars. The greater portion of the northern stars were classified from 709 plates taken with the 8-inch Draper Telescope, mounted at Cambridge. In like manner, 1,409 plates of the southern stars were used, taken with the Bache Telescope, mounted at Arequipa, Peru.It was here that Annie would conduct the work for which she would be remembered. Fleming had initially classified stellar spectra by letters from A to Q, according to the strength of their hydrogen spectral lines. Antonia Maury, another assistant working at the observatory, however used a scheme involving 22 groups from I to XXII, further adding 3 subdivisions based on the sharpness of spectral lines. Cannon saw an easier way. She simplified Fleming's scheme by removing and reordering some letters, to give the classes O, B, A, F, G, K, M. She also kept P for planetary nebula and Q for unusual stars. She also made use of Maury's numerical divisions, by introducing 10 steps, from 0 to 9.
Soon it was realised that Cannon's scheme of stellar classification was based upon the stars' temperatures, where the ordering is from O the hottest to M the coolest, and it was established that it was a suitable method. Her spectral classifications were thus universally adopted from 9 May 1922, when the International Astronomical Union passed the decision. It was with this classification method that Cannon et al. were able to publish their 9 volumes as the Henry Draper Catalogue. A further 47,000 additional classifications were made for what was to become the Henry Draper Extension, in two volumes, published in 1925 and 1949. With only minor adaptations, the method of classification Cannon implemented is still used today.
It was not long after she began her career that her work and work ethic were honoured. After finishing her studies at Wellesley in 1907, receiving her masters, in 1911, she succeeded Fleming as the Curator of Astronomical Photographs at Harvard, and in 1914 was made an honorary member of the Royal Astronomical Society. She became the first woman to receive an honorary doctorate from a European university: in 1922, Groningen University in the Netherlands awarded her a doctor's degree in mathematics and astronomy. Soon after, she was awarded the first honorary doctorate to be given to a woman by Oxford University in England :-
For hundreds of years, Oxford University has been giving honorary degrees to leading men in the fields of science and art, but for the first time, a woman was so honoured when the degree of Doctor of Science was conferred on Miss Annie Jump Cannon, of Harvard College Observatory, in recognition of a long series of valuable contributions to astronomy, chief of which is the completion of a catalogue of 225,300 stars - "The Henry Draper Catalogue of Stellar Spectra." ... Miss Cannon sailed for Europe on June first and received the degree in person. She will visit astronomers in other parts of England and France and will attend the triennial meeting of the International Astronomical Union at Cambridge, England, in July. She is a member of the Union's International Committee on Spectral Classification.In 1931, the Henry Draper Medal was presented to her by the National Academy of Sciences :-
One of the most marked distinctions in the American astronomical world was recently conferred on Dr Annie Jump Cannon, of the Harvard College Observatory at a meeting of the National Academy of Sciences in New Haven last November, when she was awarded the Henry Draper Medal for outstanding achievement in astronomical physics. Perhaps no single item of information about the stars finds its way into so many different aspects of astronomical research as does the knowledge of their spectra. In problems of distance, brightness, temperature, size, motions, distribution in space, variation, and physical structure, the spectrum of a star plays a revealing role. And it is to Miss Cannon's untiring work during the past thirty years that much of the present knowledge of stellar spectra owes its existence.In the following year she was awarded the Ellen Richards Research Prize. She turned over this money to the American Astronomical Society allowing the establishment of the Annie Jump Cannon Award, a prize given to a female astronomer, within five years of her receiving her doctorate, for her distinguished contribution to astronomy. The first award was made in 1934.
She became a member of the faculty at Harvard in 1938, appointed as William Cranch Bond, Professor of Astronomy.
Her list of achievements and career trajectory were certainly not common for a woman of her time. In this line of work, women rarely rose above the level of assistant, and many were only paid 25 cents an hour to work 7 hours a day for 6 days a week. One of the other women working in the observatory who also made significant contributions was Henrietta Swan Leavitt, who, like Annie, was deaf.
Other than her work in the observatory, Cannon played a major role in the development, and the gain in popularity, of astronomy. She helped broker partnerships and exchanges of equipment between men in the international community, assuming an ambassador-like role for astronomy. She wrote books and articles, increasing the field's status and went on to represent professional women at the World's Fair in Chicago.
Moreover, she was a member of the National Women's Party, and in 1929, the National League of Women voters listed her as one of the 12 greatest living American women. She was one of the few women ever elected to the American Philosophical Society and was one of the first women to become an officer in the American Astronomical Society.
Cannon officially retired from the observatory in 1940, but continued researching until her death the following year.
Her contribution to astronomy is seen as invaluable, impacting on many other problems and areas of research. It helped progress the science of astronomy from one of simply observation to one of great theoretical and philosophical content. During her life, she discovered about 300 variable stars, 5 novae and 1 spectroscopic binary. She manually classified more stars in a lifetime than anyone else, with a grand total of about 350,000. Not only was she very fast, but she was also accurate.
Over a career of more than 40 years, Annie not only boosted the reputation of astronomy, but also helped women gain acceptance and respect within the scientific community.
She died of heart failure following a month-long illness on 13 April 1941 in Cambridge, Massachusetts aged 77, having continued to work on astronomy until only a few weeks prior.
Article by: I J Falconer, J G Mena, J J O'Connor, T S C Peres, E F Robertson, University of St Andrews.