These beautiful wisps of gas and dust are all that remain of a star that exploded about 7,500 years ago - a supernova that would have been visible to our ancestors for several weeks.Located in the constellation Cygnus about 1400 light years away, the explosion left a ring of debris known today as the Cygnus loop. The portion of the ring in this image is Pickering’s Triangle, named after Edward Charles Pickering the director of Harvard College Observatory from 1877 to 1919.

In the early 1880s, Pickering’s team was struggling to analyze the enormous amounts of data that the observatory was receiving. He was also reportedly frustrated with the abilities and competency of his assistant. So, Pickering did a pretty remarkable thing for the time. He fired his assistant and hired his maid Williamina Fleming.That began an era at the Harvard University Observatory that helped pave the way for women in science. Over the next 40 years, more than 80 female “computers” (they weren’t called scientists or astronomers) poured over photographic plates and spectral data under the watchful eye of his former maid. Although Pickering was a pioneer in recognizing the value and contributions of women in science, he was also likely motivated by financial considerations. The women were paid as little as $0.25 a day. Fleming typically worked 60 hours a week and made $1,500 a year, much less than the least experienced male assistant at the observatory.

Many of the women on Pickering’s team went on to productive careers in astronomy. Williamina Fleming, discovered the Horsehead Nebula. Henrietta Leavitt developed a way to measure astronomical distances - a technique that’s still used today, and Annie Jump Cannon developed a system for classifying stars that’s also still in use.