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    Re: "Longitude Found" Presentation
    From: Frank Reed
    Date: 2015 Sep 16, 12:03 -0700

    Luc, you wrote:
    "The image still contains all its lovely EXIF data, including its time of creation: October 1, 2008, at 10:04:41+01:00
    link"

    Aha! Thank you. I had assumed the EXIF details would have been lost in translation from one copy to another. But that fixes the date very nicely. So it wasn't the most recent "Wednesday October 1" but the one before that in 2008. As for the time, I'm inclined to believe the wristwatch over the EXIF time since it has been my experience that relatively few photographers worry about setting the exact time on their cameras. I suppose I would give 3-to-1 odds that the watch is right, but this is undecidable, I would say, without further evidence. It's possible that Richard's watch was five minutes slow.

    Trying to have some navigational fun with this:
    How would we decide this in an emergency navigation circumstance? Assuming you're skilled at celestial navigation, and you have all the tables you need and a solar-powered calculator. You've had an electrical fault that took out several time pieces, the shortwave radio, and of course the GPS system. You're left with one passenger wearing a digital watch and another with a camera with the time set. The watch says it's 9:59:33 and the camera says it's 10:04:41. Can we live with a five-minute uncertainty in the time? If so, what would our procedures be? Better yet, how could you decide between the two? Both the owner of the digital watch and the owner of the camera swear that they set their devices to the correct time upon leaving port less than a week ago. One of them is right. What would you do?

    Frank Reed
    ReedNavigation.com
    Conanicut Island USA

       
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