NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Dip uncertainty
From: Alexandre Eremenko
Date: 2004 Dec 6, 15:58 -0500
From: Alexandre Eremenko
Date: 2004 Dec 6, 15:58 -0500
It is an interesting evidence that you present, but it is not clear what is the basis of these statements. I have NO experimental data. Only "thought experiments" Here is another one: Let us place ourselves into the situation that was already described: One observer is tall, his height is H and another is short, his height is h. Place them in such a way that they see the same common point on their horizons. So that a ray from the horizon goes to the eye of h first, then (through his head) to the eye of H. Now (this is a thought experiment!) let us remove all air over the eye of h. That is suppose that there is no refraction on the way from h to H. So the light goes straight from h to H. Then (I claim) the "refraction correction to the dip" for H will be exactly the SAME as the refraction correction to the dip for h. The ray of light is "curved" (that is changes its direcdtion) only on the way from the horizon to h. Then the same change of direction will apply at the H place, no matter whether H is on an aircraft carrier or on the peak of Tenerife on in the outer space. Now, if we restore the atmosphere, that is the air between h and H be can only get a greater correction. Alex. On Mon, 6 Dec 2004, Bruce Stark wrote: > I've dug up a couple of things that tend to confirm > what Trevor and I > believe.