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11-12-2004 Pam,
There is a translation of a letter from Synesius to his friend Paeonius concerning the gift of an instrument that may be some form of early astrolabe in Gunter, Robert, "Astrolabes of the World".  The translation was done for Gunter by some nuns who had no background in this sort of thing and is very hard to understand.  It's not clear to me whether the problem is with the letter or the translation.  In any case, the letter clearly describes some sort of instrument, but it is not at all clear that it is an astrolabe.  It could be some variation of an astrolabe of his own design or something completely different.
I'm happy to provide whatever input I can to help with your research. For example, I can send you the chapter from my book in process that outlines the history of the astrolabe and my astrolabe bibliography.  I know you are interested in the astrolabe only in the context of Hypatia, but the chapter may convince you that the material on the web about Hypatia's role in its development is incorrect.  This should not diminish Hypatia since she wrote a commentary on Ptolemy and was clearly quite knowledgeable about astronomy as it was in the 5th century.
I have been digging into my memory and I can't recall the mention of a woman in the history of early astronomy.  I know that Elizabeth I was educated in Renaissance astronomy and owned an armillary sphere, so I assume that other noble women also received this in their education.  Sadly, it appears that women were not indepently active in astronomy until the 19th century, but I would gladly be corrected on this point.  I'm sure you are aware of the role played by Caroline Lucretia Herschel in her brother's activities in the late 18th century and that she discovered eight comets on her own.
Best regards,


11-11-2004 Pam,

Despite her other accomplishments, Hypatia definitely did not invent the astrolabe.  The instrument that became the planispheric astrolabe evolved over several centuries and no one knows who combined the elements into the final  form.  Hypatia's father, Theon, wrote an astrolabe treatise that was the basis of much of what was written about early astrolabes. It is likely that Hypatia knew about astrolabes and one of her students, Synesius of Cyrene, apparently had an instrument made that was possibly a form of astrolabe. 
Some women who are prominent in current astrolabe studies are Liba Taub, curator of the Whipple Collection at Cambridge Univ.,  Sara Schechner, curator of the Harvard Instrument Collection,  and Peggy Kidwell, at the Smithsonian Museum of American History.  Marjorie Webster, curator emeritus of the Adler Planetarium and Astronomy Museum, collaborated with her late husband to build the Adler collection which is the second largest in the world.  Sharon Gibbs, currently at the National Archives, used to be active.   Laura DeAngelis of Kansas City has recently completed a sculpture that incorporates a working astrolabe.  I'm sure there are others, but these are all I can think that I have met.
Best regards,
James E. Morrison
Astrolabe web pages at

Introduction | Trends | Technology at the time | Astrolabe | Hydrometer | Mathematics | Conclusion | Bibliography