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    Re: Burton's "Nautical Tables, High Latitude Edition"
    From: Brad Morris
    Date: 2013 Feb 18, 17:02 -0500

    Hi John

    The sum total of the supplement was produced for the list, I held nothing back.  It seems as if the "High Latitude Edition" merely extended those two tables, the ex meridian and ABC tables.

    I see in your "cadet's manual" the entries for the ABC Table inputs.

    Are the ABC Tables still part of Burton's?

    Here's an example of a problem I had in mind.

    On day 0, you measure your longitude using the sun and determine it to be E166d40m.  The latitude was S77d51m.  The sun's Hour Angle was 2h24m when you determined your longitude, and the declination was S14d4m. Using your sledge-meter (a device similar to your car's odometer), you travel south 69.1 miles. You held a straight line the entire time.  This takes several days and it was cloudy the whole time.  You expect your position to now be S78d51m E166d40m, that is, 1 degree further south.

    You observe the sun crossing your meridian, the latitude is revealed to be S78d40m, that is, 11 arc minutes in error.  What is your longitude?

    According to Burton's "High Latitude Edition", there is a solution, using the ABC tables.  The very tables just posted to the list.

    Best Regards
    Brad


    On Feb 18, 2013 5:48 AM, "John Brown" <jdb0302@yahoo.co.uk> wrote:

    Brad wrote:

    "In searching the entire archive of the NavList, it appears as if we have spent no time in review of this table. There are some passing references to it by one Mr. John Brown. I suspect that is you John and that indeed you have actually used these tables, albeit some time ago. Fantastic! In your ringing positive review of these tables, you have taken up the side of defender and advocate. I'd like to give these tables a fair shake. By the evidence directly at hand, they were in use for more than 100 years (1846 through your apparent use in the 1960's."

    Yes, I am that John Brown. Another John Brown has posted on Navlist, so perhaps some of us need to adopt avatars or a numbering system. But I digress.
    I am appreciative of Burton's entire volume, not just the ABC tables, a condensed version of which is still published annually; see Reeds Astro Navigation Tables, 2013 edition. 167 years and counting!

    I did not know of the existence of this high latitude supplement to Burton's until I read your original post and I am pretty well out of my comfort zone in Antarctica in more ways than one. I am not sure what you would like me to demonstrate that isn't covered in the notes. One thought was to use the tables to determine the initial GC course to, say, a fuel dump some distance from McMurdo base, using Dlon as the hour angle and latitude of the dump as the dec. Unfortunately the range of declinations in the supplement extends to only 62 degrees, so not 'well within the span of the presented table' in this instance. I don't consider this a serious shortcoming in Burton's work.

    I dug out my old 'Cadets' Manual of Navigation and Nautical Astronomy' from pre-seagoing training days in 1960. Attached is an extract of historical interest (to me) from the period before HO 229 or HO 249 found universal acceptance at sea.

    Best regards

    John
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    Attached File: 122423.cadets-manual.pdf

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=122423

       
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