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    Re: Why are NA sight reduction tables not
    From: Gary LaPook
    Date: 2012 Apr 9, 00:38 -0700
    Well, I checked the formula that you posted and it doesn't work. This is what you posted:

    All Russian books use even simpler formula:
    sin A=(cos Lat sin LHA)/cos h.
    where A is the asimuth, h is the altitude.

    Try it again, maybe there is a typo.

    gl

    --- On Sun, 4/8/12, Alexandre E Eremenko <eremenko@math.purdue.edu> wrote:

    From: Alexandre E Eremenko <eremenko@math.purdue.edu>
    Subject: [NavList] Re: Why are NA sight reduction tables not
    To: NavList@fer3.com
    Date: Sunday, April 8, 2012, 4:26 PM


    Absolutely sure. Checked.
    Just check it, comparing with other formulas,
    using your calcultor, if you have any doubts:-)

    The asimuth it computes is between 0 and 90.
    Here is the rule to determine the quarter:

    The first letter (N or S) in the name of the asimuth quarter
    is the same as the letter in Lat, if Lat and Dec are
    of the same name.
    The first letter of the asymuth quarter is oposite to
    the letter in Lat, if Lat and Dec are of the oposite name.

    Sometimes it is not desirable to use h in the A calculation.
    For this case, there is another "Russian formula":
    cot A = (cos Lat tan Dec)/sin LHA - sin Lat cot LHA.

    Alex.

    On Sun, 8 Apr 2012, Gary LaPook wrote:

    >
    > Are you sure that is the correct formula for finding Azimuth?
    >
    > The standard formula is
    > sin A=(cos DEC sin LHA)/cos h.
    >
    > gl
    >
    > --- On Sun, 4/8/12, Alexandre E Eremenko <eremenko---purdue.edu> wrote:
    >
    > From: Alexandre E Eremenko <eremenko---purdue.edu>
    > Subject: [NavList] Re: Why are NA sight reduction tables not
    > To: NavList@fer3.com
    > Date: Sunday, April 8, 2012, 10:05 AM
    >
    >
    > Geoffrey,
    > Thanks.
    >
    > The formula for the asimuth in NA seems a little
    > more complicated than the one
    > taught by PE. I don't know what is the reason for this more complicated
    > formula.
    > All Russian books use even simpler formula:
    > sin A=(cos Lat sin LHA)/cos h.
    > where A is the asimuth, h is the altitude.
    > That's what I use.
    > It requires 3 inputs of angles to the calculator (without memory) while PS
    > requires 5
    > and NA requires 6.
    >
    > There are also modified Russian formulas optimized for the calculator with
    > one memory cell (like Casio f250), however I do not use them, because
    > they compute asimuth first and altitude second, while I need
    > only altitude in most cases for land observations.
    >
    > Alex.
    >
    > On Sun, 8 Apr 2012, Geoffrey Kolbe wrote:
    >
    >>
    >> At 16:08 08/04/2012, you wrote:
    >>
    >>> I would like to follow this discusion,
    >>> But what is the formula (for the calculator) taught by the Power Squadron?
    >>> Can anyone give me a link with this formula?
    >>
    >> <http://www.akronpowersquadron.com/NauticalTools/SightReduction/SightReduction.shtml>http://www.akronpowersquadron.com/NauticalTools/SightReduction/SightReduction.shtml
    >>
    >>
    >>> (I know two formulas for sight reduction).
    >>
    >> Why Alex, there is a world of excitement waiting for you then. ;-)
    >>
    >> Geoffrey
    >>
    >>
    >>
    >>
    >>
    >> : http://fer3.com/arc/m2.aspx?i=118813
    >>
    >>
    >>
    >
    >
    >
    >
    >
    >
    >
    > : http://fer3.com/arc/m2.aspx?i=118818
    >
    >
    >



       
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