Visual light curve of L₂ Pup from 3 January 1985 to 6 July 2013 (data from AAVSO). The dimming event started in 1994, and the stellar luminosity in the V band has not increased to pre-1994 values ever since. The observing periods for MAPPIT, VINCI, and NACO are marked in magenta, green, and blue lines, while the selected Julian date for zero pulsation phase, selected on JD = 2 446 322, is drawn as a red box. An average light curve (gray) is overplotted to guide the eye. The inset shows a magnified version of the fitted light curve over two pulsation cycles, during and right after the MAPPIT observations.