Index: trunk/doc/modules/CameraImages.tex
===================================================================
--- trunk/doc/modules/CameraImages.tex	(revision 5361)
+++ trunk/doc/modules/CameraImages.tex	(revision 5367)
@@ -863,9 +863,9 @@
 entry must contain the following user-defined parameters:
 \begin{itemize}
-\item GRID_OFFSET : maximum allowed displacement in search
-\item GRID_SCALE  : grid bin size in focal-plane coordinate units
-\item MIN_ANGLE : minimum tested relative rotation 
-\item MAX_ANGLE : maximum tested relative rotation 
-\item DEL_ANGLE : relative rotation step size
+\item \code{GRID_OFFSET} : maximum allowed displacement in search
+\item \code{GRID_SCALE}  : grid bin size in focal-plane coordinate units
+\item \code{MIN_ANGLE} : minimum tested relative rotation 
+\item \code{MAX_ANGLE} : maximum tested relative rotation 
+\item \code{DEL_ANGLE} : relative rotation step size
 \end{itemize}
 The output from this process is the statistics of the best-fit
@@ -930,5 +930,5 @@
 following function performs this operation:
 \begin{prototype}
-bool pmAstromMatchedListFit (pmFPA *fpa, psArray *st1, psArray *st2, psArray *match, psMetadata *config);
+bool pmAstromFitFPA (pmFPA *fpa, psArray *st1, psArray *st2, psArray *match, psMetadata *config);
 \end{prototype}
 This function accepts the raw and reference source lists and the list
@@ -949,4 +949,24 @@
 linear terms and the higher-order terms of the polynomial fits.
 
+An alternative to fitting the rotation of the FPA relative to the
+Tangent Plane is to treat the fitted transformation as a measurement
+of the chip within the FPA.  The following function performs this
+operation in the same way as \code{pmAstromFitFPA}:
+\begin{prototype}
+bool pmAstromFitChip (pmFPA *fpa, psArray *st1, psArray *st2, psArray *match, psMetadata *config);
+\end{prototype}
+This function accepts the raw and reference source lists for a single
+chip and the list of matched entries.  It uses the matched list to
+determine a polynomial transformation between the two coordinate
+systems.  The fitting uses clipping to exclude outliers, likely
+representing poor matches.  The \code{config} element must contain the
+information \code{ASTROM_NSIGMA} (specifying the number of sigma used
+in the clipping) and \code{ASTROM_NCLIP} (specifying the number of
+clipping iterations must be performed).  The \code{config} element
+must also specify the order of the polynomial fit (keyword:
+\code{ASTROM_ORDER}).  The result of this fit is a set of
+modifications of the components of the \code{pmChip.toFPA}
+transformation.
+
 A mosaic represents a particular set of challenges when determining an
 astrometric solution.  There is substantial degeneracy between the