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    Re: NavList 9435] Re: Multi-Moon line exercise in 2 parts
    From: Peter Hakel
    Date: 2009 Aug 10, 09:44 -0700
    I think we all agree that this is not the best way of getting a celestial fix, Jeremy himself said so.  For me this was a valuable learning experience and I thank Jeremy for sharing his measurements with us.  Many discussions on this list pertain to what to do when a better method is not available for some reason.  Recently I was explaining the merits of CelNav to some family members, and their reaction was: "Why don't you just use GPS?" :-)

    So this "rapid-fire" procedure could be a viable backup if indeed only one celestial body is observable (like during the day) and you want a fix "now" rather than performing a running fix a few hours later.  In the absence of a practical method of measuring the body's azimuth to sufficient accuracy, what else can one really do?  Another method quoted here recently (post #9376) involved measuring dh/dt, the rate of change of a body of known azimuth - say by timing the rising or setting of the Sun disk at equinox.  It is possible that there is some fundamental connection between that method and the rapid-fire procedure, since the latter also inherently includes dh/dt information.  The rapid-fire procedure is certainly more available for practical use, since you don't need to know the azimuth and you can do it at any time provided that the sky is clear enough.


    Peter Hakel


    From: George Huxtable <george@hux.me.uk>
    To: NavList@fer3.com
    Sent: Monday, August 10, 2009 7:00:29 AM
    Subject: [NavList 9459] NavList 9435] Re: Multi-Moon line exercise in 2 parts

    [...]

    latitude and longitude to about half an arc- minute (one SD). This
    "rapid-fire" procedure appears to be a way of combining large numbers of
    first-rate observations to produce a second-rate result.

    George.



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