NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2024 Jun 24, 07:07 -0700
Good day to all,
As recently announced, you will find an enclosed Attachment with my full analysis of this Spectacular Canigou Sunset on Nov 1st, 2005 .
You will see that for the Sun observed on the picture at 25.1' under the Astronomical Horizon (perpendicular to the Local Vertical), I am computing and observing a refraction of -38.2'.
On the other hand and for altitudes observed between 0° and 1° below the Astronomical Horizon I have built Augmented Standard Refraction Tables (ASRT) from just either the Éphémérides Nautiques (EN) or the Nautical Almanac (NAL) Classical Standard Refraction Tables applicable to heights from 0° to 90°.
When using the EN ASRT I am obtaining a (h true - h observed) intercept of -1.4 (+/-2) NM
When using the NAL ASRT I am obtaining a (h true - h observed) intercept of -0.2 (+/-2) NM
I am delaying the publication of this upcoming "Astronomical Refractions between 0° and 1° under the Astronomical Horizon" document by a few more days - one more week at the most - so that you all have ample time to find and derive the very simple computation formula I have been using.
Before publishing my results under the form of 2 such dedicated "Augmented Standard Refraction Tables" - one for the EN and one for the NAL - I first have gone through a careful, comprehensive and positive/satisfactory validation process fully explained in this upcoming "Augmented Refractions" document.
At the bottom of page NOTE 2 you will also notice that I end up challenging the Author's computed own results related to Astronomical Refraction, Atmospheric Refraction and Refracted Maritime Horizon Dip. With the exception of this upcoming "Augmented Refractions" document all the relevant and required data are already published there so that any [interested] NavList Member can rework this example and defeat my own results so that - again - we are all seeking to get the right answer rather than to trumpet about who is right or wrong.
Meanwhile, do not hesitate to contact me accordingly,
Kermit
antoine.m.couette[at]club-internet.fr
