A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David C
Date: 2020 Jan 31, 20:32 -0800
I did not finish commenting on the "No DR Position How Do You Get a Celestial Fix" thread because I became thoroughly confused. The more I think about it the more confused I become. The problem is this:
The intercept "distance" is a measure of angle. If the bearing is N-S then the intercept is a dlat and the scale is 1arc minute = 1 NM. If the bearing is E-W the intercept is a dlong and the departure scale is 1 arc minute = 1 * cos lat NM. So far so good. But what if the azimuth is, say, 45°. The intercept scale must be a function of lat somewhere between 1 and cos lat.
I belive that the intercept is always plotted at the lat scale, regardless of the azimuth. I cannot recall reading anything indicating otherwise.
I believe that I understand dlat, departure, dlong and plane and mercator plotting sheets but I cannot get my head around a line that seems to be neither one scale nor the other.
Any comments would be appreciated.