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    Re: Sight reduction methods
    From: Gary LaPook
    Date: 2015 Nov 4, 01:06 -0800

    I don't think so since their precision was only to the whole minute of arc and marine navigators like one-tenth minute of precision. Today small boat navigators accept that level of precision in HO 249 in the realization that obsevational errors swamp out that one-tenth minute precision. So HO 218 might be a good replacement for HO 249 on small boats where shelf space is limited and cruising latitudes are limited to a range of 10 to 20 degrees as most of us are (even much more limited.) I worked a sample problem with 2015 data and HO 218 is still producing accurate results with the correction table that I had posted before. 

    We discussed this in March 2011, see:

    http://www.fer3.com/arc/sort2.aspx?y=201103&sort=su&y2=201103&author=&subject=evaluation%20of%20h.o.%20218

    gl

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    Re: Sight reduction methods
    From: Stan K
    Date: 2015 Nov 3, 20:08 -0500

    Gary,
    I have a Volume J (latitudes 40º-44º) of HO 218, but I have never played with it.  I didn't acquire the book (at a used book store) until well after we discussed 218 here back in 2011.  Was 218 ever popular for marine navigation?
    Stan
       
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