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Re: HD 145913 > Doh, my ISP filtered this message as spam. Did the ISP, as a whole, recognized this address as spam? ;-) > So assuming for a second that the flicker I recorded is not a result of > systematic problems on my end, it is common that a period would be > apparent or can nearly random noise produce things that look like > periods in Fourier analysis? It depends on the nature of the noise. If the noise is purely random and frequency-independent, the Fourier spectrum should be that of a white noise. In many realistic cases, the things are not that simple, and there is usually a time-dependent process in noise production. It is therefore difficult to distinguish a natural signal from a noise based on the power spectrum only. It would be worth mentioning that "random walk" type noise (when stochastic noise is accumulative in time domain) produces a power law-type power spectrum. Anyway, if I remember correctly, peculiar A-type stars (Am or Ap) are equally abundant as normal A stars. So you will have sufficient chance to indeed catch low-amplitude variations in A-type stars. Regards, Taichi Kato
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