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Re: Dip observations by Carnegie Institution
From: Marcel Tschudin
Date: 2013 May 20, 11:43 +0300
From: Marcel Tschudin
Date: 2013 May 20, 11:43 +0300
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 Hirosewrote: > ________________________________ > > 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