Index: trunk/doc/release.2015/ps1.analysis/analysis.tex
===================================================================
--- trunk/doc/release.2015/ps1.analysis/analysis.tex	(revision 41307)
+++ trunk/doc/release.2015/ps1.analysis/analysis.tex	(revision 41310)
@@ -2699,4 +2699,8 @@
 \label{sec:fixed.aperture.photom}
 
+%% some notes:
+%% PV3 3pi used the STACK_THREEPI recipe for ppStack
+%% this set (PSF.INPUT.MAX = 10.0)
+
 For some science goals, a well-measured color of a galaxy is more
 important than an accurate total magnitude.  In the case of PS1, the image
@@ -2726,5 +2730,22 @@
 to smooth the model to the effective FWHM of the convolved image.  The
 entire procedure is then repeated with a target FWHM of 8 pixels
-(2\arcsec).
+(2\arcsec).  \textadd{Note that we do not attempt to restrict the
+stack image quality to match these convolution targets.  If the
+stack has an effective FWHM larger than either the 6 or 8 pixel
+targets, the convolution does not take place and the resulting
+analysis is performed on the raw stack.  In such cases, the smallest
+apertures are sensitive to seeing variations and should be avoided.
+Of the individual images, the fraction with FWHM large than 8
+pixels is (\grizy) = (9.8\%, 5.1\%, 4.9\%, 3.4\%, 3.7\%), and the
+fraction of stacks with an effective FWHM larger than this limit will
+be much smaller.}
+
+%% filter : fraction with FWHM < the given value:
+%%   2 arcsec (7.78 pix) : 10 pixels
+%% g : 0.902134021127 0.976721262999
+%% r : 0.949197642856 0.988031447337
+%% i : 0.950975372093 0.987227497659
+%% z : 0.965690586534 0.992015231573
+%% y : 0.963653738055 0.990022484542
 
 For the PV3 analysis of the $3\pi$ survey data, the fluxes are
@@ -2740,5 +2761,12 @@
 least the smallest 4 apertures.  Sources for which photometry in these
 fixed aperture are calculated have the flag bit
-\code{PM_SOURCE_MODE_RADIAL_FLUX} set.
+\code{PM_SOURCE_MODE_RADIAL_FLUX} set.  \textadd{Although these aperture are
+chosen to match the SDSS apertures, the SDSS images are measured on
+unconvolved images.  Since the median seeing for the SDSS images is
+$\sim 1.4$ arcseconds in $r$-band \citep{2007ApJS..172..634A}, our 1.5
+arcsecond aperture photometry should generally compare well to the
+SDSS aperture magnitudes.}
+
+\note{test this?}
 
 % at least out to aperture # RADIAL_AP_MIN (= 4), but no further than
@@ -2775,7 +2803,8 @@
 aspect ratios are randomly chosen in a range from 0.25 to 1.0.  The
 position angles are set by the sequence in the image and allowed to
-vary from 0 to 180 degrees.  The images are then convolved with a PSF
-model using the \code{PS1_V1} profile ($\kappa = 0.2$) and noise is
-added using Poisson statistics for the detected photons.
+vary from 0 to 180 degrees.  The images are then convolved with a
+circular PSF model using the \code{PS1_V1} profile (\textadd{FWHM = 1.0
+arcseconds, }$\kappa = 0.2$) and noise is added using Poisson
+statistics for the detected photons.
 
 For the figures below, we present results as a function of the (input)