NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Theoretical Question - Height of Eye from Shore
From: Greg R_
Date: 2007 Nov 16, 19:31 -0800
From: Greg R_
Date: 2007 Nov 16, 19:31 -0800
--- Peter Foggwrote: > Nah. If the tide changes the height of the sea close to the shore > then presumably it changes the height of the sea at the horizon to > the same extent. Yeah, that was my original thought too - since the visible horizon is only a few miles "out there" the state of the tide should be pretty much the same there as at the shoreline... > The dip correction remains the same. ...but the flaw in that argument would be what I said earlier, that the measured shoreline elevation would depend on the level of the tide at the time. And if it were in some location that had a much higher daily variation (say 10' or more), that would definitely be enough to affect the He correction (seems like it works out to about a minute for every 3 feet or so of He at these "low" levels - don't have an almanac handy right now). -- GregR --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---