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    Re: Assumed positions and plots
    From: Jim Thompson
    Date: 2004 Feb 20, 21:50 -0400

    > -----Original Message-----
    > From: Navigation Mailing List
    > [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]On Behalf Of Royer, Doug
    > Sent: Friday, February 20, 2004 8:49 PM
    > Subject: Re: Assumed positions and plots
    > Jim,one more thought on this subject of APs and EPs etc.
    > A little experiment if you are interested.
    > If you have an A.H. and the conditions are such that you can
    > attempt a round
    > of sights and you have the time take a gps reading of your pos.Set up the
    > horizon and useing the rules for spaced azimuths shoot 3 altitudes of 3
    > objects spaced over a period of time to simulate a real round of sights as
    > on a ship so as to obtain a fix.
    > Useing the sin-cosine method reduce all the sights and plot the intercepts
    > and azimuths on a plotting sheet from the gps(dr)position.
    > Turn the sheet over.
    > Useing the AP(whole degree)method use H.O. 229 or 249,reduce the
    > same sights
    > and plot the corresponding intercept and Zn from each AP on the plotting
    > sheet.
    > You may also use 1 body and take 3 sights of it over a period of time.
    > Explain to me what you see on the plotting sheet.I'm interested
    > in what you
    > observe between the 2 methods.
    Doug, thanks, I'll give this a try.  I got 150 additional sights in the
    Caribbean a couple of weeks ago, including a "good" set of 3 that met the
    specs for my compulsory 3-body twilight fix for the course.  I also got
    several noon sun sets and tried out the LAN issues that you, George and
    others raised on this list before we went down.  Documented some nice "hang
    time" curves.
    It's too damn cold to be taking sights here on our Island these days (PEI).
    And last night's "Nor'easter of '04" dumped so much snow that we'll be
    digging out for a week.  Wish I was back in the D.R.!

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