Altitude of the light scattering dust layer relative to the plane of the sky at RS Pup’s distance (assumed to be 1.8 ± 0.1 kpc), expressed in parsecs, with contour curves spaced by 0.1 pc. The field of view is 4′ × 4′, equivalent to 2.1 × 2.1 pc at the distance of RS Pup, with north up and east to the left. The nebular features located further than 1.8′ from RS Pup are masked (too low SNR).