[vsnet-chat 3645] Re: Overobserving

[Taichi Kato <tkato>]

Re: Overobserving

> But really the main reason corrections aren't made is because analysis is
> now done mostly on computers.  You take an electronic archive of data, trim
> it and clean it up, average it out or not, and then throw some software at
> it.  Then you sometimes use some, computer software based, statistical
> tests on the results, or you graph the living daylights out of them.
> 
> If you want to do some corrections you're going to have to get at the data
> on an almost "by hand" level and pick through it observer by observer etc.
> If you were doing the whole job by hand you may include a correction route
> in the analysis, without much difference in workload.

   Why not implelement the (known) correction algorithm(s) to the analysis
package?  My strategy was quite simple -- to add a constant value for
each observer, and minimize the high-frequency power (expressed in other
numerical form, however).  This can be implemented by using a simple
linear least-squares equation, and can be fully automatically done.
Other algorithms, if exist, could be implemented likewise.  This approach,
however, reduces one degree of freedom from each observers, so observers
who made only one observation is automatically given zero weight...
[Speaking of the frequency, I wonder if LPV analysts are solely interested
in low frequency structure.  If LPVs have high-frequency oscillations,
my approach may not be even valid.  I should add some theories predict
high-frequency oscillations is LPVs, especially post-maximum carbon
Miras.]

> Finally, I've got a 80% complete analysis from a long run of AF Cyg data
> from VSOLJ which clearly shows that the _tertiary_ period was quite stable
> at the current 920 day ish value between JD 2424000 and 2437000, but cored
> about a slightly shorter value twixt from the last date up to JD 2444000
> whence it returned to near 920 days.

   Is there any possibility of the stellar rotation period for such a
stable periodicity?

Regards,
Taichi Kato

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