obtain differences in flux relative to each image of the time series. To produce light curves from these differences, we measured fluxes for each star on the reference frame by using a PSF fitting software written by Ch. Alard. Short descriptions of the code, which was originally developed for the DENIS project, can be found in Schuller et al. ([@schuller]) or Beaulieu et al. ([@beau]). As can be seen in Fig.\[GalLPV\], the central region of is more compact towards the centre. Hence, the identification of variable stars towards central regions is incomplete because of crowding. The photometric zero-point correction was determined using a sample of constant stars on the reference frame that were cross-correlated with their counterparts in PaperI. To estimate a photometric error, two samples of randomly chosen constant stars common to all images of the time series were selected. Following the same approach as for the reference frame, mean zero-points were calculated from one sample of constant stars for each frame and subsequently used to remove zero-point variations between the various frames. Then, the differences between the corrected magnitudes of all stars of the second sample and the corresponding values from PaperI were determined. Their standard deviations served 