Relation between the orbital light curve (solid) and the radial-velocity curve (dashed) for an eclipsing binary with e = 0.3, ω = 225°, and i = 60°. The bottom axis shows the normalised orbital phase, while the top axis indicates the corresponding mean anomaly M. Dotted vertical lines mark the epochs of primary and secondary eclipses. For a circular, edge-on orbit, the primary’s RV minimum is a quarter of an orbital cycle (π/2) later in phase than the light curve minimum (primary eclipse); for eccentric orbits, this offset depends on both e and ω.