\(\lambda=5.5 \times 10^{-7} \,\mathrm{m}\)
Limit of resolution, \(\Delta \theta=\frac{122 \lambda}{d}\)
\(=\frac{1.22 \times 5.5 \times 10^{-7}}{3 \times 10^{-2}}=2.23 \times 10^{-5} \mathrm{rad}\)
At a distance of \(80\, \mathrm{m},\) the telescope able to resolve between two points whit are separated by \(2.23 \times 10^{-5} \times 80\, \mathrm{m}\)
\(=1.78 \times 10^{-3}\, \mathrm{m}\)