Index: trunk/doc/release.2015/ps1.analysis/analysis.tex
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--- trunk/doc/release.2015/ps1.analysis/analysis.tex	(revision 40590)
+++ trunk/doc/release.2015/ps1.analysis/analysis.tex	(revision 40591)
@@ -119,7 +119,52 @@
 % \end{verbatim}
 
-\note{the beginning section needs to be updated to mention the DR1 and
-  DR2 releases, the PV0-PV3 analysis versions, and the basic idea of
-  the IPP stages}.
+The 1.8m Pan-STARRS\,1 telescope is located on the summit of Haleakala
+on the Hawaiian island of Maui.  The wide-field optical design of the
+telescope \citep{2004SPIE.5489..667H} produces a 3.3 degree field of view with
+low distortion and minimal vignetting even at the edges of the
+illuminated region.  The optics and natural seeing combine to yield
+good image quality: 75\% of the images have full-width half-max values
+less than (1.51, 1.39, 1.34, 1.27, 1.21) arcseconds for (\grizy), with
+a floor of $\sim 0.7$ arcseconds.
+
+The \PSONE\ camera \citep{2009amos.confE..40T}, known as GPC1, consists of a
+mosaic of 60 back-illuminated CCDs manufactured by Lincoln Laboratory.
+The CCDs each consist of an $8\times8$ grid of $590 \times 598$
+pixel readout regions, yielding an effective $4846 \times 4868$
+detector.  Initial performance assessments are presented in
+\cite{2008SPIE.7014E..0DO}.  Routine observations are conducted remotely from the
+Advanced Technology Research Center in Kula, the main facility of the
+University of Hawaii's Institute for Astronomy (IfA) operations on Maui.
+The Pan-STARRS1 filters and photometric system have already been
+described in detail in \cite{2012ApJ...750...99T}.
+
+For nearly 4 years, from 2010 May through 2014 March, this telescope
+was used to perform a collection of astronomical surveys under the
+aegis of the Pan-STARRS Science Consortium.  The majority of the time
+(56\%) was spent on surveying the $\frac{3}{4}$ of the sky north of
+$-30$ Declination with \grizy\ filters in the so-called $3\pi$ Survey.
+Another $\sim 25\%$ of the time was concentrated on repeated deep
+observations of 10 specific fields in the Medium-Deep Survey.  The
+rest of the time was used for several other surveys, including a
+search for potentially hazardous asteroids in our solar system.  The
+details of the telescope, surveys, and resulting science publications
+are described by \cite{chambers2017}.
+
+%The Processing Version 3 (PV3) reduction represents the third full
+Pan-STARRS produced its first large-scale public data release, Data
+Release 1 (DR1) on 16 December 2016.  DR1 contains the results of the
+third full reduction of the Pan-STARRS $3\pi$ Survey archival data,
+idenfied as PV3.  Previous reductions \citep[PV0, PV1, PV2;
+  see][]{magnier2017.datasystem} were used internally for pipeline
+optimization and the development of the initial photometric and
+astrometric reference catalog \citep{magnier2017.calibration}.  The
+products from these reductions were not publicly released, but have
+been used to produce a wide range of scientific papers from the
+Pan-STARRS 1 Science Consortium members \citep{chambers2017}.  DR1
+contained only average information resulting from the many individual
+images obtained by the $3\pi$ Survey observations.  A second data
+release, DR2, was made available \note{20 January 2019}.  DR2 provides
+measurements from all of the individual exposures, and include an
+improved calibration of the PV3 processing of that dataset.
 
 This is the fourth in a series of seven papers describing the
@@ -128,5 +173,7 @@
 source detection and photometry, including point-spread-function and
 extended source model fitting, and the techniques for ``forced''
-photometry measurements.
+photometry measurements.  The software describe here was used with a
+single consistent set of parameters for the complete PV3 analysis,
+used for both DR1 and DR2.
 
 %Chambers et al. 2017 (Paper I)
@@ -261,6 +308,4 @@
 stand-alone C program, or as a set of library functions which may be
 integrated into other programs
-
-\note{quick discussion of the IPP analysis stages; PV0-PV3; DR1 \& DR2}
 
 Several variants of \code{psphot} have been used in the PS1 PV3