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    Re: Bligh's noon by chronometer
    From: Frank Reed
    Date: 2010 May 31, 03:46 -0700

    George H, you wrote:
    "All the timekeeper was doing was providing the correct interval from that morning observation, to noon."

    Aha, of course! You're right on the money. He was using his T.K. as a keeper of local time in this case. I've seen this before (latitude by a noon sight based on local time) but using a common watch, which is really all that's required. I do believe it was a well-known method, but it doesn't get much time in the well-known navigation manuals. Perhaps the standard Noon Sun sight was just so overwhelmingly traditional that it was not worth recommending this alternative.

    I suspect this trick would be most useful in near-overcast conditions. Though you might not see the Sun enough times to convince yourself that it has reached its peak at noon, if you can look at a local time watch (corrected for the run of longitude from when it was set earlier in the day) then you don't need to see the Sun for more than the ten or fifteen seconds it takes to get a single altitude.

    -FER


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