I have a data set that has 'kind of' constant sampling rate - it switches between 1 min and 2 min. About 70% of the times, samples are taken every 1 minute, and about 30%, samples are taken every 2 minutes.
I tried using FFT, but it didn't work because samples aren't evenly spaced. Instead I applied Lomb-Scargle transformation, and obtained a good looking plot. Upper plot is a Lomb-Scargle periodogram, and lower plot is the original sample data with varying sampling rate (1 min or 2 min).
What should I use for Nyquist Frequency in this case?