NavList:

Antoine, you wrote (to Paul):
"Your definition of a refracted semi-diameter - as I see it - is the angular separation between the point which is the refracted image of the unrefracted center and the point which is the refracted image of an(y) other point on the unrefracted diameter."

It's a very simple thing: refractional flattening of the apparent image of the Moon or Sun. Of course, on top of that, there's the very slight "smearing" of the image due to the splitting of the wavelengths. Maybe a more "clever" clearing process would slightly reduce the refractional flattening to account for that smearing.

-FER
PS: You included some comments about message technicalities which I should address. You wrote:
"First of all, and since some other NavList Members recently seem to have difficulties reading the correct Posts sequence numbering (recent Server change completed by Frank ?)"

Nope. We haven't moved yet. What are you talking about anyway, what "difficulties" with "post sequence numbering"???

You also wrote to Paul:
"EXOTIC TERMS / HTML MESSAGE
Sorry for lazily selecting directly from my keyboard a sign which more or less looks like the "smaller than" sign. Certainly this is why your software interpreted my post as an HTML message. In the future, I will carefully choose all characters only from the Windows Characters list."

Paul is the one who need to change how he operates --not you. Of course, NavList has always been about "traditional navigation" so we have to forgive a little inertia in matters of computing technology and online communication. But at a certain point, you have to join the 21st century. HTML email is normal email.