2 PHOTOMETRIC CALIBRATION  
2.1 General procedure  
2.2 SDSS data  
2.3 Stellar libraries  
2.4 Synthetic PAUS magnitudes  
2.5 Source extraction  
2.6 Statistical methodology  
3 VALIDATION AND PERFORMANCE  
3.1 Image zero point vs airmass  
3.2 Star vs image zero point  
3.3 Comparison with SDSS spectra  
3.4 Duplicate observations test  
3.5 Spectrophotometric standards  
4 SUMMARY AND CONCLUSIONS