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Peter,

I agree that errors of calculation can be quite prevalent, especially
with manual methods.  I also believe that one can eliminate those
errors with practice, as long as a reliable feedback of the actual
position is available, such as gps, a known position on or near land,
or the workings of other navigators.  One needs to detect one's errors
in the first place!  Incorporating rough checks is also good, to see
that the results make basic sense, although rough checks won't pick up
small errors such as reversing the sign of the index error.

Fred

On Saturday, Sep 20, 2003, at 22:12 US/Eastern, Peter Fogg wrote:

> There could be a wider message here, about just how difficult it can
> be to reduce a round of sights without making some sort of error along
> the way. My experience is that this tends to be more of an obstacle to
> accuracy than the shortcomings of one method over another.
>
> My own solution is to check manual results against those of an
> electronic calculator. An obvious advice is: always check the figures,
> but its only too easy to perpetuate one's own mistake, as Mike may
> have done here before finding the problem.
>
> Another approach, in the other technological direction, is to have a
> rough'n'ready quick method to compare more sophisticated results
> against. This could be plotting a new DR, or distance and bearing to
> destination, as well as calculating it.
>
> ----- Original Message -----
>
> From: Mike Burkes
> To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
> Sent: Sunday, September 21, 2003 6:41 AM
> Subject: Mike's Ocean Navigator Discrepancy Solved!
>
> Hi folks! My serious fix discrepancy ( about 17 min Latitude North of
> actual fix) stemmed from reverse sign IC application even though the
> erroneous fix was closer to DR! I emailed Peter Fogg regarding blunder
> and decided supplying more detail was "List worthy". Incidentally our
> fixes were virtually identical! I would hope that
> subsequent observations ( especially noon and Polaris Lat checks )
> would detect the error and the navigator would catch it! Any
> questions, comments. etc. would be appreciated. Thanks! Mike Burkes
>
>

   

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