Calibrated MIDI flux spectrum for different pulsation phases within the same cycle to investigate intracycle photometry variations. Each line represents a different pulsation phase within the same cycle and is computed as an average of data obtained at the respective phase ( ± 0.15). The top panel shows the example of pulsation phases 0.58 and 0.85 of cycle zero. The bottom panel shows the examples of phases 0.53 and 0.76 of cycle one. The error bars are computed as the standard deviation of the averaged photometry curves. The gray shades denote zones that are affected by atmospheric absorption.