NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Night moon sights
From: Frank Reed CT
Date: 2004 Jan 31, 03:10 EST
From: Frank Reed CT
Date: 2004 Jan 31, 03:10 EST
Trevor K wrote:
"However, I suspect that _some_ of the cut-off of the path of the Moon as
seen on the real ocean is due to wave crests obstructing the reflected
light (as Frank suggested) but that most of it results from a lack of
reflecting facets inclined at a sufficient angle to send rays towards
the observer's eye from points on the ocean's surface far away from
where the reflection would be seen given a mirror-smooth surface."
Absolutely! I agree with all of that, Trevor. I only wanted to suggest a BASIC mechanism which is able to explain the observed phenomenon. Reflection off those wave "facets" I described can shift the Moon's "shimmer horizon" away from the true horizon. The details are undoubtedly complicated. The reflecting surface created by realistic ocean waves could not possibly fit any simplistic idealized model of ocean waves (I think I alluded to that earlier). Nonetheless there's an interesting possibility that a decent model, or better yet empirical measurements, could put numbers on this puzzle. Maybe, just maybe, there's something like a 'dip short' that could be applied to Moon altitudes measured from the glowing "road" under the Moon at sea.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
"However, I suspect that _some_ of the cut-off of the path of the Moon as
seen on the real ocean is due to wave crests obstructing the reflected
light (as Frank suggested) but that most of it results from a lack of
reflecting facets inclined at a sufficient angle to send rays towards
the observer's eye from points on the ocean's surface far away from
where the reflection would be seen given a mirror-smooth surface."
Absolutely! I agree with all of that, Trevor. I only wanted to suggest a BASIC mechanism which is able to explain the observed phenomenon. Reflection off those wave "facets" I described can shift the Moon's "shimmer horizon" away from the true horizon. The details are undoubtedly complicated. The reflecting surface created by realistic ocean waves could not possibly fit any simplistic idealized model of ocean waves (I think I alluded to that earlier). Nonetheless there's an interesting possibility that a decent model, or better yet empirical measurements, could put numbers on this puzzle. Maybe, just maybe, there's something like a 'dip short' that could be applied to Moon altitudes measured from the glowing "road" under the Moon at sea.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
