We present an updated and improved description of the light curve behaviour of T Ursae Minoris , which is a Mira star with the strongest period change ( the present rate is an amazing -3.8 \pm 0.4 days/year corresponding to a relative decrease of about 1 % per cycle ) .
Ninety years of visual data were collected from all available databases and the resulting , almost uninterrupted light curve was analysed with the O - C diagram , Fourier analysis and various time-frequency methods .
The Choi-Williams and Zhao-Atlas-Marks distributions gave the clearest image of frequency and light curve shape variations .
A decrease of the intensity average of the light curve was also found , which is in accordance with a period-luminosity relation for Mira stars .
We predict the star will finish its period decrease in the meaningfully near future ( c.c .
5 to 30 years ) and strongly suggest to closely follow the star ’ s variations ( photometric , as well as spectroscopic ) during this period .