[lsst-dm-stack-users] Problem visualizing astrometry matches; getX() fails

[Dominique Boutigny]

Hi,

Yes, I confirm that I spent some time debugging the astrometry on CFHT 
images and I was able to visualize the astrometry using debug.py as it 
is described by Paul. Nevertheless my problem was more to understand why 
the astrometry solver was not converging and I finally understood the 
problem by superimposing the identified sources on top of the original 
image. The problem was due to sources associated to cosmic rays screwing 
up the astrometry. It was solved by adjusting the FWHM of the initial PSF.

Dominique
Le 23/06/2014 08:10, Paul Price a écrit :
> On Jun 22, 2014, at 3:35 PM, Michael Wood-Vasey wrote:
>> * Question to list: Has anyone succeeded in visualizing astrometry matches using display('astrometry', ...)?
> Dominique Boutigny has been down a similar path recently (in the "CFHT reprocessing" room on HipChat; the log is there to read), so I hope he will chime in with his experience.  You might be able to access his writeup on his wiki: http://lsst.in2p3.fr/wiki/index.php/CFHT_data_processing_with_LSST_stack
>
> Please be aware that the displays (i.e., lsstDebug) were originally put together for developers to debug code that they're looking at.  The design and implementation are both on the table for reworking in the near future.  The layer that's built into the Tasks (calling Task.display) was my attempt to standardise some things, but it hasn't really been exercised much, and clearly some of it hasn't survived the multiple transitions it's gone through over the past few years.  I'll have a look at this particular instance to see what needs to be fixed.
>
> I think you would be better served using the debugging features in lsst.meas.astrom.determineWcs.  Put in your debug.py:
>
> import sys
> try:
>     import lsstDebug
>     print "Importing debug settings..."
>     def DebugInfo(name):
>         di = lsstDebug.getInfo(name)        # N.b. lsstDebug.Info(name) would call us recursively
>         if name in (
>             "lsst.meas.astrom.determineWcs",
>             ):
>             di.display = 3
>             di.showLinear = True
>             di.verbose = True
>             di.frame1 = 1
>             di.frame2 = 2
>             di.frame3 = 3
>         return di
>     lsstDebug.Info = DebugInfo
> except ImportError:
>     print >> sys.stderr, "Unable to import lsstDebug;  not setting display intelligently"
>
>
> P.
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-- 
Dominique Boutigny  -  CNRS / CC-IN2P3
Now at SLAC National Accelerator Laboratory

Kavli Building - Room 221
Mail     : boutigny at in2p3.fr -  boutigny at slac.stanford.edu
Office   : +1 650-926-5759   -  Cellular : +1 774-232-0912

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