The flux calibration is done in this method by taking the ratio between the signals from the target and the calibrator along the observing time and then deriving the mean and median values, which are scaled by the known flux from the calibrator chosen. Since the time evolution of the response for a given pixel is determined mainly by the illumination level NO background subtraction to the observed target should be done. If the customize option is chosen, an intermediate menu, as shown in Fig. If a pre-selection is to be made, then a list of calibrators with their status as active or inactive will appear, as shown in Figure 2. The selection corresponding to this figure is the default one at the time of releasing PIA V7.3.
More weighting is given to signals after advanced exposure time.
Mean and median yeld to the flux scaling factor. The best calibration is obtained when the ratio along time is constant and close to unity. The fraction of the measurement which is used to compute the ratio can be selected a posteriori interactively. It is similar to all main levels' PIA windows. The main variables plotted are the ratios between source signal and calibrators used.