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    Re: The taxonomy of refraction
    From: John Huth
    Date: 2011 Jan 7, 18:01 -0500
    Marcel - 

    In your case, yes.   In this case, I'm not so sure.  I think that that island is just on the edge of the geographic range, so high points poke above the horizon and low points disappear.    I'm not entirely sure, but I've seen this island break up into small pieces and also appear as a continuous strip.   Also, it slants at an angle from my house, so the closest point is about 5 miles away and then slopes off to about 8+ miles.   From the height of my house - 25 ft, I can sometimes see the close part as a continuous strip and then it breaks up into islets and then disappears.   Under other conditions, it appears to be continuous all the way to the end.   I'm assuming that a lot of this is due to the effective horizon shifting under differing atmospheric conditions.   

    I sent those photos to Andy, as you suggested and gave him the conditions.   I'll report back what he has to say.


    John H. 

    On Fri, Jan 7, 2011 at 10:08 AM, Marcel Tschudin <marcel.e.tschudin@gmail.com> wrote:
    > I guess my first-order thinking is that the apparent horizon is going
    > further out as the day progresses...
    I presume you mention this in the context of the second photo having
    gaps next to the lighthouse and the adjacent building. I could imagine
    that this is only a "colour feature" from how the "missing" parts are
    illuminated by the sun. The way how they are iluminated may have
    turned them to the same blue colour as the sky. I observed this some
    time ago in the context of "ships in the sky" where part of the sea
    received the same colour as the sky. You find these photos here

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