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    Re: Dip Angles from Blue Hill Observatory
    From: Bruce J. Pennino
    Date: 2013 Apr 2, 18:23 -0400
    Does some sort of polarizing filter improve the sight?

    ----- Original Message -----
    Sent: Tuesday, April 02, 2013 6:06 PM
    Subject: [NavList] Re: Dip Angles from Blue Hill Observatory

    Bruce thank you for sharing your practical experiences. You wrote:
    "But, the horizon had gray sky over dark gray water; very faint horizon line."

    Yes, that sounds familiar. You were lucky having been able to notice the faint horizon line. In most of my photos (Hs measurements) which had to be discarded it was because the apparent horizon could not be (clearly) recognised. This can be a result of haze/fog or of the sea having near the horizon the same color as the sky. Such features may then cause the appearance of a wrong apparent horizon, one which is only the separation line between two colors of the sea or between sea and fog/smog. I presume that such errors are more likely when measuring with a sextant or theodolite; a photo allows the situation to be analysed in more detail.


    View and reply to this message: http://fer3.com/arc/m2.aspx?i=123276

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