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[ATM] Draper mirror
Yesterday, in preparation for a lecture on the life of Henry Draper to be given on December 7, 2007 at 8:00 p.m. at the Andrus Planetarium, part of the Hudson River Museum on Warburton Avenue in Yonkers, NY. I visited the country home and observatory of Henry Draper MD on Broadway in Hastings on Hudson, NY.
My intention was to obtain photographs of the grounds as well as Henry's mirror, which was referred to in an earlier post on this list. At the museum, I was met by some very pleasant people, Muriel Olsson and her granddaughter, Emily, a second grader graciouisly gave me a tour of the facility and the archives. I was stunned by the amount of effort that was expended by these ladies in archiving all of the material from the Draper family in their possession as well as other Hastings-on Hudson memorabilia. The museum was fascinating!
The museum has Dr. Draper's 15.5 inch mirror which he made in 1861-1862. It is neatly packed away and is in pristine condition. I believe it was of plate glass, probably a porthole and was thin, about an inch or so in thickness. I believe it is of a long focal lenght however. I asked if I could borrow it to test under a double pass autocollimator. I would also like to measure it for such characteristics as actaul diameter, runout, thickness and weight to better establish the type of glass used. (all testing is non-destructive) I believe that at the time this mirror was made, it was the largest mirror in the US and was one of the first glass telescope mirrors in the US (Speculum metal was not very practical)
The analysis of the mirror would be a pleasant addition to my lecture. My request still has to go through the Board of Directors for the Hastings Historical Society, but I understand that it will likely be granted.
By the way, the society still has many of Draper's telescope parts in their archives. They don't know what most parts are. I assisted a volunteer curator in identifying some parts such as cameras. I also found partrs of what may have been his clepsydra and his clock drive.
If you have the time, the society is open Monday and Thursday from 10:00 to 1:00. (The ladies lunch at noon). The trip might be well worth it.
Francis J. O'Reilly
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