May 6, 1878 Between the clouds, Miss Spalding obtained 7 photographs of Mercury on the Sun. It is a comfort to me to be able to plan and do a new kind of work. The large telescope worked better than usual, Clark having just been to the Observatory.
Maria Mitchell and her students photographed the Sun on every clear day and as such were able to photograph the transit of Mercury and the rarer transit of Venus – the planet for which Maria had calculated the ephemeris for the US Nautical Almanac for many years. She was the first woman computer for the Nautical Almanac and likely, the federal government. In its archive collection, the MMA has several images that Maria and her students completed of transits of the sun, including the one of Venus which was taken by Elizabeth Rebecca Coffin, an artist of some renown and also a child of two Nantucket Quakers.
Apparently, Alvan Clark had recently visited Maria and the Vassar College Observatory and made some adjustments to the telescope. He was the premier telescope maker in America – and the man who made Maria’s five-inch – monies for it were a gift from the Women of America – a subscription overseen by Elizabeth Peabody.