Joining the "over 10km" optical club

This morning I got a note from Stuart G8CYW which surprised me:

"Roger,

It has occurred to me that you have joined a "select" group, who have made an optical contact over 10km here in the UK with modulated LEDs. I had a quick count up of the people I know about and I do not think there are 10 yet. (probably more I do not know about though) .....so no small achievement."

So apparently very few of the people experimenting with 481THz red LED optical communications have broken the 10km barrier for 2-way QSOs. This surprised me. At the same time I am even more encouraged to continue this fascinating area of amateur radio as there is so much more I can do. The beauty of this is that test equipment needs are basic, skills needs well within my capabilities, and the results when success comes are extremely satisfying.