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    Re: Sobel and Longitude. was:: Re: David Thomson and his lunar tables
    From: Frank Reed
    Date: 2010 Mar 20, 18:29 -0700

    Ken Muldrew, you wrote:
    "Although instructors of navigation may have wished for such zeal in their students, without historical evidence, such as logbooks, one should be skeptical. The logbooks that Frank has studied, and written about here, provide a different view of how navigators depended on lunars in that era. It may be that his sources (primarily American whalers) have a bias toward a certain type of navigator, but anyone proposing that hypothesis is obligated to provide some evidence to support it. Frank's historical evidence from primary sources has to be considered a trump card in this debate until such time as other sources can be shown to contradict, or at least temper, his conclusions."

    Yeah, there is a certain fantasy view that all of us have nurtured at one point or another that has those navigators somewhere around 200 years ago shooting lunars at every available opportunity. But that's not history. History is what navigators actually did, and there is ample evidence of their practice in the logbooks. For the American whaling fleet which dominated the Pacific (from New England!) in the mid-19th century, there are 15,000 logbooks extant. This is a massive store of information that has only barely been mined for navigational information. I've studied just over a hundred logbooks from the 19th century. Lunars were typically used for a few days every two weeks around First Quarter and Last Quarter. They were typically Sun-Moon lunars. This wasn't exclusive by any means. Something like 80-90% of lunars were Sun-Moon lunars. I have, in fact, described some of those less common star lunars in NavList posts in the past few years. These lunars were used in support of "longitude by account" from about 1800-1835, roughly, and to support "longitude by chronometer" from 1835-1850, roughly. After that, they're gone. And by the way, on American vessels, I haven't found any evidence of lunars before 1800, but I haven't looked much. I know of letters from that period stating that they are "new" to Nantucket or "new" to Salem c.1800, but that's all.

    Also, while there is the possibility that the whalers were less navigationally rigorous in their work, there is also the possibility that they were far MORE interested in lunars than other vessels at sea. The idea that the whaling captains were some sort of navigational idiots is another Huxtablism.

    And finally, the logbooks I have examined personally are only about two-thirds whaling logbooks. For example, the logbook of the Sabina that I mentioned in a recent post was a "gold rush" ship --a passenger vessel-- though with many whalemen aboard no doubt given their port of origin. And the Reaper (I posted a logbook page with a fully worked lunar a few days ago) was a typical Boston merchantman. Their use of lunars was fascinating and not at all what you might expect from the textbook accounts as in Bowditch and Norie.

    I encourage any and all of you on NavList to go visit some of the research libraries with collections of old logbooks. That's where the history of navigation is to be found. Not in Bowditch. Not in 20th century histories. But in the primary source material, the logbooks of the actual voyages. For those of you in New England, probably the most appealing place to visit is the Providence Public Library (which is a privately-endowed library, open to the public). It's conveniently located off the interstate, the curator/librarian is very helpful and maybe a little too happy to have visitors, and the research collections room is like something out of a movie.


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