Dear Aimo, Ha! Yes I like your metric version...
1. Take your height above the ground in meters and multiply by ten 2. Add a half 3. Take the square-root 4. The result is the distance to the refraction rised horizon It is spoilt slightly by the instruction to "multiply by ten". That, of course, is what the decimal system is all about so I cannot complain! Best wishes Frank --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial