A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2013 Jan 10, 00:28 -0800
|Before you spend a lot of effort drawing in the location of the sun,|
I didn't realize at the time (many years ago) I made these modifications that the ecliptic, due to the projection used for the star base, would plot as a circle which makes it much easier to place on the star base. The radius of the ecliptic is 90° on the declination/latitude scale and the center is placed on the arctic circle at its intersection with the right ascension of the the sun at the time of the winter solstice which is 270° on the star base. To determine where to place the center of the ecliptic I placed a straightedge from 90° to 270° and drew a line extending from about 70° north to about 30° south. I placed the red disk over it and marked 23.5° south. I then set the drawing compass to extend from the pole to the equator and swung an arc from 23.5° south so that it placed a mark on the line at 66.5° north. Then I used this mark as the center to draw the ecliptic,
See my prior posts about modifying a 2102-D.
--- On Tue, 1/8/13, Gary LaPook <garylapook---.net> wrote: