Hello there! How you doing?
Am wondering if you came up with an answer to the last question I asked? Relating to the longest line of sight photograph, covering a distance of 275miles. This is not the first time I have reached this point in the conversation only to never hear from the other person again! Does this mean you've simply had enough talking about this subject? Or perhaps it means you don't have an answer to the question? Either way I would love to know.
Same answer applies as the answer to your issue with seeing the white sandy beach through your telescope. Line of sight depends on MANY more variables than just the curvature of the earth.