NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Just getting started
From: Alexandre Eremenko
Date: 2007 Jan 18, 10:06 -0500
From: Alexandre Eremenko
Date: 2007 Jan 18, 10:06 -0500
On Thu, 18 Jan 2007, Fred Hebard wrote: > Gary, > > I believe objects for adjusting the index > correction have to be > several miles away before parallax is insignificant. One mile minimum, two miles are more than enough. > The lake may also not be large enough > to give a nice horizon (several > miles). It is nice if you do not see the other shore. > There is a dip short table > in Bowditch to accommodate this > problem. Dip is irrelevant for IC checking using the horizon. All you need for IC checking is a remote (at least 1 mile away) straight line. An electric wire will do the same if you are able to see an electric wire 1 mile distant. There is actually some disagreement, what is the best object to check the IC. Some recommend a star, some recommend the horizon, and Frank Reed recommends the Moon. My own experience shows that Sun is the best, a VERY SHARP horizon probably goes second. Alex. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
