NavList:

Hello to all,

Further to our last post on this topic, valuable information has been published meanwhile in NavList  (here and here) with simple formulae to compute - or better: estimate - the Atmospheric refraction between 2 points at a finite distance.

Now having at hand all required tools to finalize this puzzle, I have computed an Observer's position which falls less than 200 yards from the Position the Photographer himself admitted to me. Did he really disclose the exact position of his own magic spot? Anyway ... the computed end position certainly falls in the vicinity of this hidden spot and it should permit some meaningful and hopefully quick and easy fruitful research on site, especially since the lateral error is very narrow - certainly [much] less than 20 ft wide on each side - given the powerful MonViso - Superga alignment of the picture.

BTW, all computations on ground were performed on the WGS84 Ellipsoid in 3D.

As for the very low altitudes encountered here, all below 2°, I am impressed at the quality of the Atmospheric Refraction formulae earlier published for a standard and unperturbed atmosphere (which certainly is the catch).

While I was expecting prediction errors of up to 2 to maybe 3' or even 4' in such an environment, I wish to share here the very nice surprise to observe that my computations are matching the true world to better than 0.5' on all vertical refracted coordinates.

As for me this fully concludes this topic.

Do not hesitate to contact me through e-mail.

Thank you for your Kind Attention,

Kermit

antoine.m.couette[at]club-internet.fr