NavList:

Louis Carrier, you wrote:
"I found that this image of the Rampion wind farm, photographed from a place near Pagham (UK), is so interesting that I tried to add my humble contribution to this thread. I was fortunate enough to find online an interactive "marine chart". I then was able to extract the coordinates (latitude and longitude) for each wind generator I thought was on the image."

That's wonderful. I'm glad you found it as intriguing as I did! And thank you for posting your analysis. The position you found [50°45.410'N,  0°44.740'W] for the observer's "point of view" is interesting and certainly viable and believable. It's a bit funny at first sight -- if you drop those coordinates in Google Maps, as here, the pin falls a few hundred meters offshore. That looks bad. But then if we switch to the satellite view, we can see --aha!-- the beach has grown since the vector map data was compiled in Google Maps.

Did you try any sensitivity testing on your position solution? If you wiggle the input numbers slightly, does the resulting "fix" change? And did you try changing the radius of the Earth? Sounds crazy at first, but this is a standard and legitimate means of incorporating so-called "terrestrial" refraction. Add ten or twenty percent to the Earth's radius and see if anything changes. :)

I've described a couple of times how variable refraction would cause those turbines to visually rise and fall, as if the Earth is breathing... I also mentioned that my analysis suggests the possibility that the efficient mixing of the air, created by the turbines themselves, may actually eliminate much of the refractive variability, so in the case of wind farms, we might only be able to observe unusual refraction phenomena on calm days. I'm attaching an animated GIF comparing two photos I took a decade ago here on Narragansett Bay. The camera was in exactly the same position, and there was no obvious sign of variation in the atmospheric conditions. Yet the view is significantly different on two different days. Note: if the image looks static, open it in a separate web browser tab. Most browsers will run the GIF animation automatically.

Thanks again for sharing your analysis.

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA

File: