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: Peter Fogg
Date: 2007 Nov 17, 14:20 +1100
From: Peter Fogg
Date: 2007 Nov 17, 14:20 +1100
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. The dip correction remains the same. On Nov 17, 2007 1:45 PM, Greg Rudzinskiwrote: > > The Dip correction is referenced off the oceans surface therefor if > you are on land the height of tide would have to be taken into > account. If you are on a floating dock then the tide will have no > effect on the dip. > > Greg Rudzinski > > > On Nov 16, 6:30 pm, "Greg R." wrote: > > OK, here's a question for the theorists on this list... If I'm doing > > sextant shots from shore (vs. on the water itself), do I need to factor > > in the height of the tide into my He corrections? > > > > I actually surveyed one of my favorite locations with a handheld > > transit/bubble level device and a surveyor's rod (to get an elevation > > measurement accurate to within a couple of inches or so), but it dawned > > on me that measurement would only be valid for the state of the tide at > > the time. > > > > This particular location (Ventura, CA) doesn't have a huge tidal range > > - maybe 3-4 feet - but it got me to thinking that other locations with > > a much greater tidal range would probably be affected enough to where a > > correction would be necessary to get the same accuracy that you'd > > expect from being on the water. > > > > -- > > GregR > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---