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.
April, 1878. I called on Prof. Henry at the Smithsonian Institute. He must be in his 80th year. He has been ill and seems feeble but is still the majestic old man, unbent in figure and undimmed in eye. I always remember when I see him, the speech of Miss Dix, “He is the true-est man that ever lived.
In Washington, D.C. for a meeting of the officers of the Women’s Congress – the Association for the Advancement of Women meetings ̶ Maria stopped by to visit a friend and something of a mentor, Professor Joseph Henry. A physicist and professor, Henry was the first secretary of the Smithsonian Institute. His feebleness was telling – Henry would die about a month after Maria’s visit with him in May 1878. Henry was friendly with William Mitchell as well – they all ran in the same circles so to speak – and Henry came to Maria’s support/aid several times including when she wanted to take a leave of absence from the U. S. Nautical Almanac during her European trip. Those calculations for the Almanac were tedious and trying to complete them and travel was not going to be easy. When she asked for a leave from the work, the Almanac refused and Henry wrote a letter to support her year or so leave. I think the Almanac was just afraid to lose Maria completely. She would only resign several years into her professorship at Vassar – once she was sure that she was settled into the job completely.