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Re: http://fer3.com/arc/m2.aspx/Dip-observations-Carnegie-Institution-Hirose-may-2013-g24098

Thank you, Paul, for having dug out this old publication. Based on the
observations the author arrives at a formula which leads to dip values
which are almost 10 percent smaller than those resulting from the
formula generally used these days (Bowditch, N.A.).

It will be interesting to see which of these dip formulae correlates
best with my sunset Hs measurements once the HoE estimates from
originally +/- 20% have been improved to hopefully better than +/-
10%.

Marcel


On Mon, May 20, 2013 at 2:36 AM, Paul Hirose  wrote:
> ________________________________
>
> Bowditch (volume 1, 1984) mentions the results of 5000 dip measurements
> at sea by the Carnegie Institution. I haven't found the source document,
> but in 1918 a Carnegie scientist, Willliam J. Peters, summarized 3031
> dip observations in "Results of Dip-of-Horizon Measurements Made on the
> Galilee and Carnegie, 1907-1917." [Terrestrial Magnetism and Atmospheric
> Electricity, volume 23, number 2 (June 1918), page 47]
>
> A scan is online at archive.org:
>
> http://archive.org/details/journalofgeophys22ameruoft
>
> To download (not view online), click "HTPPS" in the "View the book" box.
> The article begins on page 261 of the document.
>
> Peters says the visible horizon was never more than 2.4 minutes above or
> 2.0 minutes below the geometric horizon. He concludes dip tables that
> ignore temperature are sufficiently accurate for navigation.
>
> --
> 
>
> : http://fer3.com/arc/m2.aspx?i=124098

   

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