Orbital inclination and mass constraints for NGC 1851A. The solid and dotted lines represent the nominal values and 1-σ constraints for the post-Keplerian parameters (red: $\dot{\omega }$, cyan: γ, purple: h₃) obtained with the DDH binary model. Bottom left plot: cos i versus the companion mass (M_c); Bottom right plot: Pulsar mass (M_p) versus M_c. The grey portions on the two plots indicate the regions excluded for M_p < 0 and sin i > 1 respectively. The normalised 1-D pdfs for cos i, M_p and M_c are shown in the top left, top right, and right panels.