This is the list of the blazars regularly monitored by the GASP Project of the WEBT.
To reduce offsets between different datasets when building light curves, the source magnitude must be calibrated with respect to the recommended reference stars, as indicated in the corresponding “Photometric Sequence” page.
For the sources with important contributions from the host galaxy, a specific value for the photometry aperture radius is also recommended, in order to optimize the subtraction of the galaxy light contamination.