In this work, a portable cosmic-ray telescope was designed, assembled and operated to measure the cosmic-ray induced atmospheric muon flux at ground level. The instrument was entirely characterized and modeled from the point-of-view of detector efficiency, energy detection window and counting rate. Experimental data are reported for the characterization of the muon flux at sea level (43 ∘ N of latitude) in terms of vertical muon intensity and zenithal angle dependence.