P Cygni was discovered in 1600 AD during an outburst when it reached 3rd magnitude. After another outburst in 1655 the star is now showing irregular photometric variations with an amplitude in V of ~ 0.2 magnitude. Because of these variations and of its peculiar spectral characteristics, P Cygni has been classified as anything between supernova and W UMa system. However, its light curve is unlike that of any other star and P Cygni could well be considered the first discovered LBV.

Over the last three years an accurate photoelectric light curve has been put together.

It is based on observations made by a number of amateur and professional observers around the world and shows the following features:

+ Variations are irregular with maxima and minima every 1 - 2 months;

+ The brightness variations seem to show more scatter when the star is faint.