SIMBAD references

In this campaign on the Luminous Blue Variable star P Cygni, we are trying for the first time, by way of contemporaneous measurements of photometric V brightness and Hα equivalent width (EW), to realize a long-term monitoring of the intrinsic Hα line flux. Photometric and spectroscopic observers started this campaign in November 2008 in order to continue former investigations whose results are based on multi-daily averaging of V and EW. The campaign results enable us to represent the quantitative behavior of the Hα line flux for the time span August 2005 to December 2011, which reflects variabilities in mass-loss rate, stellar wind density, and the ionization structure.