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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Dip Angles from Blue Hill Observatory
From: Marcel Tschudin
Date: 2013 Apr 3, 01:03 +0300
Marcel
From: Marcel Tschudin
Date: 2013 Apr 3, 01:03 +0300
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."But, the horizon had gray sky over dark gray water; very faint horizon line."
