The fundamentals of astronomy for beginners
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Annie Maunder
Ezzy Pearson celebrates the achievements of the early 20th century’s great solar scientist
This March, English Heritage commemorated the lives of two great solar scientists, Annie Maunder and her husband Walter, by placing a blue plaque on their former home on Tyrwhitt Road in Lewisham, south London. The pair spent decades observing and studying the Sun, even giving their name to a period of low solar activity at the end of the 17th century now known as the Maunder Minimum.
English Heritage’s blue plaque scheme, which began in 1866, honours notable people with distinctive circular signs on the buildings they lived and worked in. Twelve new plaques are erected annually, each one considered by a panel of historians, artists, scientists and writers. Howard Spencer, English Heritage’s Senior Historian, explains why the Maunders have been selected. “As well as their important work on sunspots, solar photography and the debunking of the canals-on-Mars myth, the Maunders were also active in promoting amateur astronomy,” he says.
Annie Maunder was born Annie Russell in County Tyrone, Ireland, in 1868. She excelled at school and earned a place at Girton College, Cambridge. Despite being her college’s top mathematician, restrictions of the day meant she was unable to receive a degree: her achievements occurred during a time when being a woman meant she was barred from academic recognition, and much of professional astronomy.
In 1891, she took a position at the Royal Observatory Greenwich as a ‘lady computer’, mathematically calculating the positions and brightnesses of stars by hand. In the late 19th century, this tedious, low-paid role was performed by university-educated women who were denied the higher status jobs of their male counterparts.
Partners in science
Annie began work at Greenwich’s solar observatory, taking daily photographs of the Sun with the Royal Observatory’s Dallmeyer photoheliograph, which she then analysed for sunspots and reported the findings to colleague, Edward Walter Maunder. The two built on the research of the 19th-century German astronomer Gustav Spörer, by analysing sunspot patterns going back over centuries.
They noticed that from 1645 to 1715, sunspots had been exceedingly rare, and this timespan is now known as the Maunder Minimum. Annie’s contributions, however, went unrecognised at the time, as the bar on women being awarded degrees had the knock-on effect that she couldn’t be listed as an author on the paper, an oversight that did not sit well with Walter.
“Walter Maunder was a founder member of the British Astronomical Association (BAA) in 1890 and Annie had two spells as the editor of its journal,” says Spencer. “It was their avowed aim that this new organisation should be more accessible to women, and would ‘afford a means of direction and organisation in the work of observation to amateur astronomers’ – many of whom, of course, went on to make significant discoveries themselves.”
Over time, the two grew closer than mere colleagues and married in 1895. They lived together at two houses on Tyrwhitt Road, including the one being honoured with a blue plaque, continuing their work. Annie was listed as an author on several of Walter’s papers, investigating the relationships between sunspots and magnetic storms.
“It was during their time on this road that they published the 1904 article, with its famous butterfly diagram’,” says Spencer, referring to their diagram (above) showing the latitude positions of sunspots over time. As sunspots tend to appear nearer the equator at certain times of the 11-year solar cycle, these have a lobed shape that resembles a butterfly.
In 1907, she finally published her first solo paper, titled, ‘An analysis of the formidable sunspot data set that had been gathered at the ROG, covering 1889–1901’. It was a huge report, analysing data from a useful span of years and showing asymmetries in the east–west parameters of sunspots.
One of the most important works for the Maunders, however, was their jointly written book entitled, The Heavens and their Story, published in 1908. It was an early example of a popular science book aimed at a general audience, featuring several pictures of the Sun and Milky Way taken by Annie, and it makes frequent references to Hilly Fields, a park near to Tyrwhitt Road.
Annie worked alongside Walter until he died in 1928, and then carried on researching until her death in 1947.
As well as the plaque, her work in bringing astronomy to the public is recognised by the Royal Astronomical Society’s Annie Maunder medal for Outreach and the Annie Maunder Prize for Image Innovation at the Astronomy Photographer of the Year Awards.
Following the Sun
The Maunders’ studies of the Sun from took them from their Lewisham home all over the world
When the Maunders married, Annie was forced to give up her official position at Greenwich, but continued to work alongside her husband unofficially – including accompanying him on the many expeditions he took around the world to see and photograph eclipses.
Though Annie had to pay her own way on these trips, she was given a grant from her alma mater, Girton College, Cambridge, which she used to buy a camera with an unusually large field of view. Armed with this camera and unbound by the expedition rules and itinerary, she could often venture off and take images the official astronomers could not. One particularly dramatic example is her ‘longest-ray’ photograph taken in 1898. This showed a coronal streamer 14 solar radii in length – the longest on record at the time.
Despite her unofficial status, Annie was often included in the expedition write ups, such as one written in 1901, which included her description of ‘plume-like rays’ in the corona, a term astronomers still use today.
Dr Ezzy Pearson is BBC Sky at Night Magazine’s news editor