Re: High speed photometry results V455And

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Fri, 28 Sep 2007 07:56:10 -0400 · jop_at_astro.columbia.edu

Nice results from Don and Donn.  This signal has been back for at least 
8 days, and likely more.  The 134 s signal is intriguing, but I'd guess 
not real. Some implementations of ANOVA can be misled by subharmonics - 
since a fold at twice the true period will have a lot of variance (with 
a double-humped waveform).  A Fourier transform (power spectrum) never 
makes this mistake... though it has other drawbacks (e.g. failure to 
award credit for power at harmonics, leading to a lack of overall 
sensitivity... and enormous confusion sown by amplitude changes).

We've actually been tracking the (presumed rotation) signal for the last 
three years - including a last point just 3 days before eruption.  So 
we'll be very well set to compare the precise periods/phases 
before/during/after the DN eruption.  First time ever!

I hope to see a few of you at the fall AAVSO meeting - good chance to 
discuss the eruption, among other things.

joe