NavList:

Frank,

For altitudes below zero degrees, you are challenging my very sentence :

"Just use the Nautical Almanac refraction tables" .

Maybe I should have stated instead: "build some computation approach based on the Nautical Almanac refraction tables only and nothing else".

From just the Refraction Tables, and through a reasonable/ not so unreasonable mathematical approach, a rather simple one if you know how to proceed, it is indeed possible to "figure out some realistic and reliable value" - i.e. approximate to +/-1' or 2' (any better claim would be non-sense here) - for the refraction of the Sun on the picture.

And by the way, the observed/actual Sun refraction on the picture can be easily derived from the data already given in my last post .

So we already have at hand the observed refraction value which will be used as a benchmark.

Because this topic is not covered in any Navigation Treaty I know of, this is the special interest of this puzzle and I am looking forward to reading contributions here, including yours if you so desire.

*******

And in reply to your query:

this top of page picture - i.e. http://canigou.allauch.free.fr/Refract_atm.htm - is the previously faulty "Spectacular Sunset" link (in my very first post) you just requested and which seems to work for my second post.

Thanks in advance for correcting this "Spectacular Sunset" faulty link in my very first post.

This Sunset is indeed spectacular, don't you think so ?

Thanks for your Kind Attention, and

Best Regards,

Kermit