The Harvard Computers was a group of woman who were hired by the director of the Harvard Observatory, Edward Charles Pickering. From 1877 to 1919 he hired around 80 women to serve as human “computers”. They were hired instead of men to process large amounts of astronomical data. Some say these women were chosen because they could be hired for far less than their male equivalents. Whatever the reasoning, one thing is very true… the work of these women often goes unappreciated.

“Edward Charles Pickering (director of the Harvard Observatory from 1877 to 1919) decided to hire women as skilled workers to process astronomical data. Among these women were Williamina Fleming, Annie Jump Cannon, Henrietta Swan Leavitt and Antonia Maury. This staff came to be known as “Pickering’s Harem” or, more respectfully, as the Harvard Computers. This was an example of what has been identified as the “harem effect” in the history and sociology of science.

It seems that several factors contributed to Pickering’s decision to hire women instead of men. Among them was the fact that men were paid much more than women, so he could employ more staff with the same budget.This was relevant in a time when the amount of astronomical data was surpassing the capacity of the Observatories to process it.

The first woman hired was Williamina Fleming, who was working as a maid for Pickering. It seems that Pickering was increasingly frustrated with his male assistants and declared that even his maid could do a better job. Apparently he was not mistaken, as Fleming undertook her assigned chores efficiently. When the Harvard Observatory received in 1886 a generous donation from the widow of Henry Draper, Pickering decided to hire more female staff and put Fleming in charge of them.

As a result of the work of the women “computers”, Pickering published in 1890 the first Henry Draper Catalog, a catalog with more than 10,000 stars classified according to their spectrum. Pickering decided to hire Antonia Maury, a graduate from Vassar College, to reclassify some of the stars. Maury decided to go further and improved and redesigned the system of classification. It was published in 1897, but was largely ignored. Afterwards Pickering decided to hire Cannon, a graduate of Wellesley College, to classify the southern stars. As Maury had done, Cannon also ended up redesigning the classification system of the spectra and developed the Harvard Classification Scheme, which constitutes the basis of the system used nowadays.

Although some of Pickering’s female staff were astronomy graduates, their wages were similar to those of unskilled workers. They usually earned between 25 and 50 cents per hour, more than a factory worker but less than a clerical one.”

~ Wikipedia

From all the stories, one of my personal favorites belongs to Henrietta Swan Leavitt. Pickering had tasked Levitt to study variable stars. What she discovered became an early standard that helped future astronomers.

“… Leavitt noted thousands of variable stars in images of the Magellanic Clouds. In 1908 she published her results in the Annals of the Astronomical Observatory of Harvard College, noting that a few of the variables showed a pattern: brighter ones appeared to have longer periods. After further study, she confirmed in 1912 that the Cepheid variables with greater intrinsic luminosity did have longer periods, and that the relationship was quite close and predictable.

Leavitt used the simplifying assumption that all of the Cepheids within each Magellanic Cloud were at approximately the same distances from the earth, so that their intrinsic brightness could be deduced from their apparent brightness (as measured from the photographic plates) and from the distance to each of the clouds. “Since the variables are probably at nearly the same distance from the Earth, their periods are apparently associated with their actual emission of light, as determined by their mass, density, and surface brightness.”

Her discovery is known as the “period-luminosity relationship”: The logarithm of the period is linearly related to the star’s average, intrinsic luminosity (which is defined as a logarithm of the amount of power radiated by the star in the visible spectrum). In Leavitt’s words, taken from her study of 1,777 variable stars recorded on Harvard’s photographic plates, “a straight line can be readily drawn among each of the two series of points corresponding to maxima and minima, thus showing that there is a simple relation between the brightness of the [Cepheid] variable and their periods”.

The period-luminosity relationship for Cepheids made them the first “standard candle” in astronomy, allowing scientists to compute the distances to galaxies too remote for stellar parallax observations to be useful. One year after Leavitt reported her results, Ejnar Hertzsprung determined the distance of several Cepheids in the Milky Way, and with this calibration the distance to any Cepheid could be accurately determined.

Cepheids were soon detected in other galaxies, such as Andromeda (notably by Edwin Hubble in 1923–24), and they became an important part of the evidence that “spiral nebulae” are actually independent galaxies located far outside of our own Milky Way. Thus, Leavitt’s discovery helped to settled the “Great Debate” on whether the Universe was larger than the Milky Way, and thus changed our picture of the Universe forever.

The accomplishments of the American astronomer Edwin Hubble, who established that the Universe is expanding, were also made possible by Leavitt’s groundbreaking research. “If Henrietta Leavitt had provided the key to determine the size of the cosmos, then it was Edwin Powell Hubble who inserted it in the lock and provided the observations that allowed it to be turned,” wrote David H. and Matthew D.H. Clark in their book Measuring the Cosmos. To his credit, Hubble himself often said that Leavitt deserved the Nobel Prize for her work. Gösta Mittag-Leffler of the Swedish Academy of Sciences tried to nominate her for that prize in 1924, only to learn that she had died of cancer three years earlier (the Nobel Prize is not awarded posthumously).”

~ Wikipedia

I highly recommend reading, “Miss Levitt’s Stars” by George Johnson if you would like to take your experience beyond Wikipedia <3 

But don’t just stop there… all of these women deserve your curiosity. if not to learn more about their lives, then to learn about the science they loved.