From: Michael Koppelman <lolife
Date: Mon, 20 Mar 2006 12:54:20 -0600
To: arne <arne

I guess I'm suggesting a babystep. Our goal is the most simple method  
that gives us the most information. If you can run a CCD camera and  
capture data and then successfully perform photometry on your images,  
you are probably capable of opening the resulting text file in Excel.  
That is how I calculate the standard deviation of the comp stars (or  
and analysis.

The 1/SNR method basically tells us how many photons you got. The  
standard deviation of a constant star tells us (in aggregate) about  
your seeing, whether clouds came through, how well your aperture  
centering worked, etc. You can't measure a variable better than you  
can measure a standard star (with some assumptions about magnitude  
and color).

My original post was to suggest that the comp star standard deviation  
method is barely more difficult than 1/SNR but gives us much more  
information.

Cheers,
Michael Koppelman

On Mar 16, 2006, at 12:02 PM, arne wrote:

> Problem is that what is "most useful" to you is also not "darn easy."
> If you use standard analysis packages, they will report errors for
> a given frame, but not standard deviations of a set of frames, nor
> calculate midpoints, etc.  You have an ancillary program that does  
> that.
> But more pertinent, even such techniques do not address systematic
> errors such as the lack of transformation or not applying extinction
> and it takes some education to obtain the right number.
>
> I'm planning on talking to software vendors later this year (after my
> Travel Period From Hell) about requiring a common output format for
> use by the AAVSO, and as part of that I'll request common error  
> analysis.

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