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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: shadow stick trivia question
From: Byron Franklin
Date: 2009 Oct 23, 12:38 -0700
From: Byron Franklin
Date: 2009 Oct 23, 12:38 -0700
Using my star finder to see how the shadow works. The bearing of the body moves the shadow from point to point. the changing HT. causes the tip of the rod to throw a shadow, from the base according to the amout of change in body HT. Zenith Distance seems to be the controlling factor, the near by stars changed HT. quickly, so changed the HT. of the shadow more than the farther stars at the near my horizon. So summer would really change the shadow, winter would be straighter. Thats the way I saw the problem? On Oct 16, 7:15�am, Apache Runnerwrote: > Frank - > > You're right. � I realized the error I had in visualizing it. � A straight > line will have a shadow on the equinox that's due east/west. � It's tough to > visualize because at the moment of sunrise/sunset, the length of the shadow > is infinite, so it's really a limit. I really need to go calculate this. > Just for fun, I found the following applet: > > http://www.ies.co.jp/math/java/conics/hidokei/hidokei2.html > > > > On Thu, Oct 15, 2009 at 9:34 PM, wrote: > > > Well, I'm never 100% sure, but I think that's right. The cone collapses to > > a plane for a great circle... a plane intersecting another plane (the local > > ground) yields a straight line. > > > -FER- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com -~----------~----~----~----~------~----~------~--~---