A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2019 May 7, 10:08 -0700
There must have been a discussion here of the single-body fix by James N. Wilson but I can't find it, only this paper.
Everything is clear (to me) regarding the determination of LAN time and - therefore - the longitude. I have several possibly silly questions:
- the only HS's one must fully correct (IE, dip, refraction, parallax) are those taken to determine the highest Sun's altitude - for the latitude; the series of the pre-LAN and post-LAN altitudes may be used "as-are" (in HS "raw" form) - since one only needs the timing from them. Right?
- there is no need for any (extra) correction of East-West component of a velocity because it is provided automagically by the plotting process itself. Vessel's E-W movement just makes the plotted slopes more|less steep - in direct proportionality with the East-West component of a velocity. For example, if one goes West as fast as the Sun - there will be no maximum at all (an extreme example). Right?
There is a purely-graphical way of obtaining the fix (no tables and coefficients from the article required).
I'd like to read the discussion of this single-body fix. All comments welcome.
Thank you in advance.