[Aavso-photometry] Differential vs. absolute magnitudes

[gianlucaros at gmail.com]

I still have some confusion about differential vs. absolute
magnitudes. If I have understood properly transformation coefficients
improves the accuracy of the measurements and zero point is necessary
only for all sky photometry. Concerning the new AAVSO format that asks
to specify differential vs. absolute magnitudes, does this request
mean to specify that magnitudes are obtained with either differential
or absolute photometry? Is the latter possible only if you have the
standardized magnitude of your comp star? Can I find information about
standardized magnitudes for comp stars in the photometric table of the
VSP or shall I calculate myself? I apolologize for asking something
that perhaps has been already addressed by some of you.
Gianluca