Changes between Version 56 and Version 57 of Sa10Problems

Timestamp:

Dec 13, 2012, 11:44:39 AM (14 years ago)

Author:

eugene

Comment:

--

Sa10Problems

@@ -43 +43 @@
        * a.  We don't use this flag (so then why is it there?)
   * A2: 12% have ra_err > 0.1 deg (same for dec_err), and 70% have ra_err = 0 (same for dec_err) 
-     * a. For the 12% that have raerr > 0.1, the majority come from (ng+nr+ni+nz+ny) = 0 or only a few suspect the calculation is goofy because there are few points to calculate raerr. '''(GENE??)''' '''gene notes that ra/dec err are in units of arcsecs, and he notices that pretty much everything is within 1 arcsec. '''
+     * a. For the 12% that have raerr > 0.1, the majority come from (ng+nr+ni+nz+ny) = 0 or only a few suspect the calculation is goofy because there are few points to calculate raerr. '''EAM : ra/dec err are in units of arcsecs, selecting from the DVO db I see a max value of just of 1 arcsec'''
      * a. For the 70% that have ra = 0, I did a count(*) and grouped by objInfoFlag. I repeated this for raerr!=0.  Here's what I find:  if 0x00090000 (avg position used and fitted) is not set, it has raErr = 0 (this is the majority of things).  If 0x0040000 (mean astro could not be measured) is set, may fall into either, with a preference for raerr!=0.  why do so many not have 0x00090000? are those entirely the stacks? the majority of those have a detection in a filter (for the raErr=0, and flag = 4194304).  If I do a similar query but without the restriction on flags (same raerr = 0), I find a whopping majority have NO ng/nr/ni/nz/ny, ie, they are stacks.
        *  '''We need to make it very clear that raErr / decErr is calculated from an average of single frame detections, and may not be present at all when it is a stack with no or few single frame detetctions '''
@@ -57 +57 @@
   * A7: General magnitudes comments:  (GENE?)
      * 1. gMeanPSFMag - gStackPSFMag is bimodal: two peaks one at -0.03 and one  at 0.12 (clearly separated) and not really the case for other bands
-       * a. '''EAM : I do not see this effect in SAS 11 (but have not plotted it for SAS 10).  the figure below shows g(PSF,EXP) - g(PSF,STK) vs g(PSF,EXP) and a histogram of the difference.  I do not 2 peaks, but I am concerned about the 0.05 mag offset'''. 
-       * [[Image(delta.g.png,120px,right)]]
+       * a. '''EAM : I do not see this effect in SAS 11 (but have not plotted it for SAS 10).  the figure at right shows g(PSF,EXP) - g(PSF,STK) vs g(PSF,EXP) and a histogram of the difference.  I do not 2 peaks, but I am concerned about the 0.05 mag offset'''. [[Image(delta.g.png,250px,right)]]
      * 2. ?MeanKronMag & ?MeanKronMagerr: they span a ridiculous range (which  is not the case for ?MeanPSFMag and ?MeanPSFMagerr, hence the reason to flag it)
        * a. '''EAM : in DVO, the mean kron mag range is not strange'''