SU Tau is a well-observed R Coronae Borealis star. Like the prototype of the class, SU Tau undergoes very dramatic fadings of several magnitudes that occur seemingly at random; the star may remain constant between 9th and 10th magnitude for several years, and then exhibit wild drops in brightness to 17th magnitude or fainter.
AAVSO observer John Bortle noted that SU Tau began another precipitous fade in November of 2011 after not quite recovering from its fade of the last few seasons. Where it will go next is anyone's guess...
Prepared By: Matthew Templeton