ABSTRACT
Mira variables are characterised by the fact that neither the periods nor tbe amplitudes are constant. With Mira, tbe interval between successive maxima may be several days either longer or shorter than the mean value of 332 days. some maxima the star may become realJy bright; in 1779 it is said ro have reached the first magnitude, almost equal to Aldebaran, and l remember that in February 1987 I made it of magnirude 2.3, more or less equal ro tbe Pole Star. However, at otber maxima the greatest brightness may be as low as magnirude 4. One can never tell; no two cycles are exactly alike. Yet it is always easy enough to identify because it is so obviously red; its spectrum is of type M.
