Problem $13[$ Rayleigh Criterion $]$

In J$.$R$.$R$.$ Tolkien's The Lord of the Rings $($volume $2,$ p$.32),$ Legolas the Elf claims to be able to accurately count horsemen and discern their hair color $($yellow$)5$ leagues away on a bright, sunny day. Make appropriate estimates and argue that Legolas must have very strange$-$looking eyes, have some means of nonvisual perception, or have made a lucky guess. $(1$ league $\backslash (\backslash$approx $3\mathrm{.}0\backslash$mathrm$\{$mi$\}\backslash ).)$ I encourage you all to take some measurements of your own eyes to try to get an estimate for proportions here.