NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Use of Marine Sextants in Aircraft
From: Fred Hebard
Date: 2018 May 9, 22:17 -0400
From: Fred Hebard
Date: 2018 May 9, 22:17 -0400
David,
Your slides 2 and 3 had a central ray originating at the location of the observer, defining the height of a right triangle with two dashed-line sides; that is not there. Assume the observer is in the center of the ship. His position defines the angle between the ends of the shadow. The right triangles are defined by his two observation lines of sight.
Fred Hebard
On May 9, 2018, at 3:01 PM, David Pike <NoReply_DavidPike@fer3.com> wrote:David, I agree that the sun could be regarded as a point source for this purpose. I think your drawing needs to be redone to reflect this, rather than having the rays converge at the airship. An open problem! How nice. Fred Hebard
Fred
Did you scroll down and look at slides 2 & 3? The Sun's parallel rays are the yellow ones in slide 2. I thought you were going to pick me up on the distance-off problem. I realised the moment I hit the 'Send' button that it will only work with the ship's length if the ship is beam on to you. Using the height of the top hamper would be independent of aspect, but the angle subtended would be about around ten times smaller. DaveP
