Energy fluxes of 1 TeV photons from PSR B1259−63 as a function of the true anomaly (top panel) and of the binary separation distance (bottom panel). The measurements were carried out by HESS during the 2004 (black full symbols – fluxes using a bin width of 2 days) and 2007 (red empty symbols – monthly fluxes) periastron passage, respectively. Squares denote pre- and circles post-periastron measurements. The vertical grey boxes indicate the location of the stellar disc inferred from the best-fit geometrical parameters from radio data. The vertical dashed and dotted lines denote the positions of the stellar equatorial plane along the pre- and post-periastron orbits, respectively (Bogomazov 2005).