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Changes between Version 35 and Version 36 of stacking_coverage.20130307


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Timestamp:
Apr 26, 2013, 4:02:28 PM (13 years ago)
Author:
watersc1
Comment:

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  • stacking_coverage.20130307

    v35 v36  
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    55The following table shows the comparison between the current MD09 deep stacks (deeptest) and the reduction with the current ppStack changes (MDtest or comparison below).  I used four skycells that Mark noted were particular bad.  The images show that the new code does a better job retaining images and that cleans up some of the i-filter skycell issues.  However, this improvement does not extend to y/027, which still has a clear region of high variance.  The profiles in the next column show a slice across the image from 2000-2500pixels in X (red) and Y (blue).  The median variance for that profile from the weight image is also displayed (in green and purple).  This illustrates that the new reduction does remove some of the un-modeled image variance jumps that were present in i/041 and i/061.  The final column shows the profile of a star in the stack for both the deeptest (red) and comparison (green) stacks, along with the Gaussian fit sigma value for each.  These profiles suggest that even though the comparison target PSF is larger than in the deeptest stacks, the stellar profiles in the unconvolved stack do not change significantly.
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     7It should be clear that the deeptest is not a reference stack used for difference images, nor is it an absolute deep stack.  It was constructed as a test for examining the results of stacking large numbers of inputs in ppStack.  However, there is no other stack available for these skycells that have comparable or greater coverage, and so it is used as the basis to compare the set of ppStack changes used in the MDtest stacks.
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