I'm a visual observer and I'm looking for visual magnitudes of objects I'm going to observe. Example: EW And. The VSX and the GSVS show: 10.8 - 11.8 p. SIMBAD has fluxes: 8.98 V, 12.14 B (=> B-V = 3.16).
Is there a formula that lets me transform the range from p-band to visual? Since the range is about 1 magnitude one guess would be 8.98 - 9.98 vis, assuming that the flux 8.98 V is at maximum. I also thougth that subtracting the B-V value from the p-values (assuming that p is in the blue spectrum) could give the answer, but that would mean a range 7.6 - 8.6 which looks wrong.
Since many ranges in VSX and GCVS are not in the visual range I would appreciate any help. Thanks in advance,
P.S. I often look a light curves, they are a great help but in this case (EW And) there aren't any observations.