Re: Working on Data

[Tom Droege <tdroege2@earthlink.net>]

While this looks awful, I think Michael uses the correct term 
"annoying".  If I do a "by eye" estimation of sigma, then these residuals 
look about like what I see looking at the whole data set.

The question is, "do we care?"

I would certainly like to fix this problem. However, it is not very 
significant in the range where the data is really useful, V mag 9 to 
13.  In this range other errors dominate.  One can argue that one should 
fix each problem as it arises and thus beat down the overall noise.  Yep!

I figure that after we do this and one or two things more that the data 
will look nicer and will give users more confidence in it's quality, but 
that it really won't be any better for it's purpose.  Sigh!  I wish this 
were not true, but I am not very optimistic that we well very much improve 
the data taken in this suburban location.

Still, I am optimistic that the data is useful.  For the moment it may be 
the only such data available.

Michael, if you work out a fix for this, will it require rerunning all the 
data?

I would not mind doing this, it is only a couple of months of feeding CD's 
to hungry computers.  Possibly we can just reprocess the .cal files.  In 
either case, I want to process everything in a consistent way.

Tom Droege

At 06:24 PM 7/9/03 -0400, Stupendous Man wrote:
>I think that the answer is "yes" in V-band (which is where the
>scatter at the bright end is most annoying), and "no" in I-band.
>Take a look at these pictures of residuals as a function of position
>on the chip (for a very particular subset of all star -- details
>in an upcoming Tech Note):