We study the 1.28 million short cadence Kepler data points ( Q5-Q14 ) for RR Lyrae covering 24 cycles of the Blazhko variation , and more than one half of the 4-year modulation of the Blazhko variation .
This very rich data set clearly shows variability of the 0.5667 day pulsation period ( from 0.5655 to 0.5685 day ) with each Blazhko cycle , as well as a variation of the Blazhko period itself ( from 39.2 days at amplitude maximum to 38.4 days at amplitude minimum ) during the 4 year modulation , as well as a rapid increase in Blazhko period as the new cycle commences .