Examples of PIONIER squared visibilities collected on RS Pup on the night of 18 February 2015, close to the minimum angular diameter phase (top panel), and on 31 December 2015, close to maximum angular diameter (bottom panel). The solid line is the best-fit uniform disk visibility model, and the dashed lines represent the limits of the ± 1σ uncertainty domain on the angular diameter. The (u,v) plane coverage is shown in the upper right subpanels, with axes labeled in meters.