CLEANed power spectrum of 1SWASPJ001321.94-425511.2 from 10^-8 Hz to 10^-4 Hz. The top panel shows the power spectra of the original and randomised light curves after deconvolution with the CLEAN algorithm whilst the bottom panel shows the raw (or “dirty”) power spectra of the actual and randomised data. Peaks due to the actual signal can be seen more clearly once noise due to the convolution of the signal with the window function has been reduced. The red line in the top panel is the noise threshold calculated for frequencies below 2.3 × 10^-6 Hz (equating to Blazhko periods of at least 5 days).