Simulated CTA view of 1FGL J1018.6−5856 orbital variability. Upper panel: flux modulation of 1FGL J1018.6−5856 throughout the orbital phase as observed with H.E.S.S. (black symbols, in units of 10⁻¹² ph cm⁻² s⁻¹ for E >  0.35 TeV) and simulated for 5 h of observation with the CTA (red symbols, in units of 10⁻¹³ ph cm⁻² s⁻¹ for E >  1 TeV). Middle panel: flux relative error in the case of simulated CTA observations of 30 min (blue filled squares) and 5 h (red open squares). Lower panel: uncertainty of the photon index Γ in the same cases.