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Alvan Clark Research in the Adler’s Collections

During my research in astronomy I have learned that the astronomical community is a most generous one. They have been willing to share their time, thoughts, and resources. I have, on a number of occasions, used such resources at the Adler and have found the staff there no less generous. 

My most recent research deals with amateur astronomy in the 19th century. I am trying to ascertain the degree of public interest and commitment to astronomy demonstrated in a number of telescopes of that period. Alvan Clark telescopes were delivered to institutions and individuals, professional and amateur. The Adler’s collection includes business documents, i.e. licenses, receipts, and correspondence. It also includes personal memorabilia, letters, and photographs.

“Davidson’s Survey of Northern California” (Alvan Clark and Sons Business and Family Papers, Adler Planetarium Collections).

“Davidson’s Survey of Northern California” (Alvan Clark and Sons Business and Family Papers, Adler Planetarium Collections).

I found materials at the Adler that responded specifically to my needs. I also found materials at the Adler that piqued my interest for further research. For example, there was a photograph labeled “Davidson’s survey of Northern California,” presumably referring to George Davidson of the U.S. Coast Survey. This photograph portrayed eighteen individuals including several women, and numerous telescopes. My first thought was that this was surely evidence of amateur participation in the science of astronomy. In the center of the photograph is a structure that looks like football goal posts topped with two discs. I have communicated with an individual at the Lick Observatory regarding this photograph. He believes this might portray an example of an eclipse or transit of Venus expedition. I, too, thought this likely as some of the individuals, including at least two women, seem to be sitting with writing or drawing implements. In that period sketches were commonly made during astronomical events such as those of a solar corona during an eclipse. My Lick contact made some speculations on the purpose of the goal post structure. Perhaps the discs were useful in blocking out the Sun precisely to better catch an image of the solar corona during an eclipse, or a contact of Venus during a transit. I had never heard of the use of such a device and am now hoping to uncover more about it. I will need to communicate with the History of Astronomy Department of the American Astronomical Society.

These were days well spent at the Adler. I found what I was looking for. I also found intriguing items I was not looking for. Subsequent communication with others of the astronomical community enabled me to pass this interest on. I am grateful to the helpful and congenial staff of the Adler Planetarium for this positive experience. 

Adler visitors can view Alvan Clark telescopes on display in the exhibition Telescopes: Through the Looking Glass.

Written by Stella Cottam, researcher at the Adler Planetarium.

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