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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Measuring Dip in the 18th Century
From: Alexandre Eremenko
Date: 2013 Dec 29, 01:57 -0500
From: Alexandre Eremenko
Date: 2013 Dec 29, 01:57 -0500
It works, and it is very interestng. Actually the graphs show that they obtained better results with a simple cross-staff. Either it was better made, or the observer did a better job. And it is significantly better than 10' Alex. > If that doesn't work, try googling "hilster backstaff" > On Dec 29, 2013 1:33 AM, "Brad Morris"wrote: > >> ------------------------------ >> >> >> http://www.dehilster.info/index.php?doc=http://www.dehilster.info/instrumenten/davis-quadrant/index.html >> On Dec 29, 2013 1:26 AM, "Alexandre Eremenko" wrote: >> >>> ------------------------------ >>> >>> >>> Brad, >>> >>> >http://www.dehilster.info/index.php?>doc=http://www.dehilster.info/instrumenten/davis-quadrant/index.htmlto >>> >>> Unfortunatey, this reference does not work:-( >>> >>> Perhaps I did not make my point clear. Let me try again. >>> We see a dip table made in XVI century. >>> We can easily check it by comparing with modern almanac. >>> It does not show 10' errors, does it? >>> >>> Conclusion: They could measure angles in XVI century with >>> about 1' accuracy. >>> Now I ask: with what device? I conjecture that this was something >>> similar to >>> backstaff. >>> >>> On my opinion, all arguments about GPS and modern >>> obsession with many digits >>> which >>> Frank and you give, are not related to this question. >>> >>> Alex. >>> >>> >>> >>> >>> >>> >>> : http://fer3.com/arc/m2.aspx?i=126014 >>> >> : http://fer3.com/arc/m2.aspx?i=126015 >> > > > : http://fer3.com/arc/m2.aspx?i=126017 > > > >
