Changes between Version 8 and Version 9 of IPP_Progress_Report_20120402

Timestamp:

Apr 10, 2012, 1:52:10 PM (14 years ago)

Author:

eugene

Comment:

--

IPP_Progress_Report_20120402

@@ -5 +5 @@
 
 === Eugene Magnier ===
+
+ * spent time helping Chris with false positives & writing up the current state for the PS1SC.
+ * Looked a bit into the Kron mags using Peter D. test set and applying a very simple moments / flux analysis with user-controlled apertures.  I can confirm that I recover the model mags (with expected kron aperture bias) if I use the provided Kron radius.  I do not recover the Kron radius if I start with the Kron radius; I need to use a larger aperture.  Michael Wood-Vasey has volunteered to look at psphot issues with me, so I pointed him at some of these measurements.
+ * discussions with Edouard Bernard & Eddie S. about the faint-end bias & psphot vs DAOphot comparisons.  Edouard's DAOphot measurements show the faint end bias.  Looking at the DAOphot-reported sky levels, however, gives pretty strong evidence that we cannot blame the psphot-measured sky on the faint end bias.  First, the sky values found by DATAphot (after psphot has removed the sky model) are, as expected, generally quite close to zero, with a possible small (0.2-0.5 DN) positive offset.  Second, the faint-end-bias has more or less the same amplitude for a given magnitude value (in this dataset), and do not seem to correlate with the small changes in the reported DAOphot sky levels.  Finally, and most conclusive, the DAOphot sky levels are, if anything, generally slighlyt positive, while the faint end bias has the sense that the psphot values are too small -- this is the wrong direction.   I think need to look elsewhere.  I've asked Edouard to send me his measurements for a comparison dataset.
+ * looked into some of the remaining outlier images in the big 3pi dvo database.  It looks like I marked detections as 'poor' if they had the 'OFF_CHIP' flag raised. For a subset of images, this flag was raised for all measurements, so those images could never be tied to the rest of the database through relative photometry.  I'm also looking into some of the other images that failed to be pulled into the overall relative photometry system, but this is going a bit slowly. 
 
 === Serge Chastel ===