Index: /trunk/psastro/src/psastroFixChips.c
===================================================================
--- /trunk/psastro/src/psastroFixChips.c	(revision 20270)
+++ /trunk/psastro/src/psastroFixChips.c	(revision 20271)
@@ -6,253 +6,256 @@
 bool psastroFixChips (pmConfig *config, psMetadata *recipe) {
 
-  bool status;
-
-  bool fixChips = psMetadataLookupBool (&status, config->arguments, "PSASTRO.FIX.CHIPS");
-  if (!status) {
-      fixChips = psMetadataLookupBool (&status, recipe, "PSASTRO.FIX.CHIPS");
-  }
-  if (!fixChips) return true;
-
-  // identify reference astrometry table
-  // if not defined, correction was not requested; skip step
-  pmFPAfile *astrom = psMetadataLookupPtr (NULL, config->files, "PSASTRO.MODEL");
-  if (!astrom) return true;
-
-  // select the input data sources
-  pmFPAfile *input = psMetadataLookupPtr (NULL, config->files, "PSASTRO.INPUT");
-  if (!input) {
-      psError(PSASTRO_ERR_CONFIG, true, "Can't find input data");
-      return false;
-  }
-
-  // acceptable limits
-  double pixelTol = psMetadataLookupF32 (&status, recipe, "PSASTRO.PIXEL.TOLERANCE");
-  if (!status) psAbort ("missing recipe value");
-
-  double angleTol = psMetadataLookupF32 (&status, recipe, "PSASTRO.ANGLE.TOLERANCE");
-  if (!status) psAbort ("missing recipe value");
-
-  // make sure the astrometry model is loaded.  de-activate all files except PSASTRO.MODEL.
-  // supply the input concepts so the model is defined using the RA, DEC, POSANGLE of the input
-  // image.
-  psFree (astrom->fpa->concepts);
-  astrom->fpa->concepts = psMemIncrRefCounter (input->fpa->concepts);
-  pmFPAfileActivate (config->files, false, NULL);
-  pmFPAfileActivate (config->files, true, "PSASTRO.MODEL");
-
-  pmFPAview *view = pmFPAviewAlloc (0);
-
-  // files associated with the science image
-  if (!pmFPAfileIOChecks (config, view, PM_FPA_BEFORE)) {
-      psError (PS_ERR_IO, false, "Can't load the astrometry model file");
-      return false;
-  }
-
-  // we now have a set of chip solutions and a set of prediction measure the overall
-  // offset and rotation of the two systems by comparing the chip corners, projected onto
-  // the focal plane (all 4 to prevent solutions tied to a single corner)
-
-  psVector *xObs = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
-  psVector *yObs = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
-  psVector *xRef = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
-  psVector *yRef = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
-
-  int nPts = 0;
-
-  pmChip *obsChip = NULL;
-  while ((obsChip = pmFPAviewNextChip (view, input->fpa, 1)) != NULL) {
-      if (!obsChip->process || !obsChip->file_exists || !obsChip->data_exists) { continue; }
-
-      // set the chip astrometry using the astrom file
-      pmChip *refChip = pmFPAviewThisChip (view, astrom->fpa);
-
-      psRegion *region = pmChipPixels (obsChip);
-      psPlane ptCP, ptFP;
-
-      ptCP.x = region->x0; ptCP.y = region->y0;
-      psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
-      xObs->data.F32[nPts] = ptFP.x;
-      yObs->data.F32[nPts] = ptFP.y;
-      psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
-      xRef->data.F32[nPts] = ptFP.x;
-      yRef->data.F32[nPts] = ptFP.y;
-      nPts ++;
-
-      ptCP.x = region->x0; ptCP.y = region->y1;
-      psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
-      xObs->data.F32[nPts] = ptFP.x;
-      yObs->data.F32[nPts] = ptFP.y;
-      psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
-      xRef->data.F32[nPts] = ptFP.x;
-      yRef->data.F32[nPts] = ptFP.y;
-      nPts ++;
-
-      ptCP.x = region->x1; ptCP.y = region->y1;
-      psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
-      xObs->data.F32[nPts] = ptFP.x;
-      yObs->data.F32[nPts] = ptFP.y;
-      psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
-      xRef->data.F32[nPts] = ptFP.x;
-      yRef->data.F32[nPts] = ptFP.y;
-      nPts ++;
-
-      ptCP.x = region->x1; ptCP.y = region->y0;
-      psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
-      xObs->data.F32[nPts] = ptFP.x;
-      yObs->data.F32[nPts] = ptFP.y;
-      psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
-      xRef->data.F32[nPts] = ptFP.x;
-      yRef->data.F32[nPts] = ptFP.y;
-      nPts ++;
-
-      psFree (region);
-  }
-  xObs->n = yObs->n = xRef->n = yRef->n = nPts;
+    bool status;
+
+    bool fixChips = psMetadataLookupBool (&status, config->arguments, "PSASTRO.FIX.CHIPS");
+    if (!status) {
+	fixChips = psMetadataLookupBool (&status, recipe, "PSASTRO.FIX.CHIPS");
+    }
+    if (!fixChips) return true;
+
+    // identify reference astrometry table
+    // if not defined, correction was not requested; skip step
+    pmFPAfile *astrom = psMetadataLookupPtr (NULL, config->files, "PSASTRO.MODEL");
+    if (!astrom) return true;
+
+    // select the input data sources
+    pmFPAfile *input = psMetadataLookupPtr (NULL, config->files, "PSASTRO.INPUT");
+    if (!input) {
+	psError(PSASTRO_ERR_CONFIG, true, "Can't find input data");
+	return false;
+    }
+
+    // acceptable limits
+    double pixelTol = psMetadataLookupF32 (&status, recipe, "PSASTRO.PIXEL.TOLERANCE");
+    if (!status) psAbort ("missing recipe value");
+
+    double angleTol = psMetadataLookupF32 (&status, recipe, "PSASTRO.ANGLE.TOLERANCE");
+    if (!status) psAbort ("missing recipe value");
+
+    // make sure the astrometry model is loaded.  de-activate all files except PSASTRO.MODEL.
+    // supply the input concepts so the model is defined using the RA, DEC, POSANGLE of the input
+    // image.
+    psFree (astrom->fpa->concepts);
+    astrom->fpa->concepts = psMemIncrRefCounter (input->fpa->concepts);
+    pmFPAfileActivate (config->files, false, NULL);
+    pmFPAfileActivate (config->files, true, "PSASTRO.MODEL");
+
+    pmFPAview *view = pmFPAviewAlloc (0);
+
+    // files associated with the science image
+    if (!pmFPAfileIOChecks (config, view, PM_FPA_BEFORE)) {
+	psError (PS_ERR_IO, false, "Can't load the astrometry model file");
+	return false;
+    }
+
+    // we now have a set of chip solutions and a set of prediction measure the overall
+    // offset and rotation of the two systems by comparing the chip corners, projected onto
+    // the focal plane (all 4 to prevent solutions tied to a single corner)
+
+    psVector *xObs = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
+    psVector *yObs = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
+    psVector *xRef = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
+    psVector *yRef = psVectorAllocEmpty (4*input->fpa->chips->n, PS_TYPE_F32);
+
+    int nPts = 0;
+
+    pmChip *obsChip = NULL;
+    while ((obsChip = pmFPAviewNextChip (view, input->fpa, 1)) != NULL) {
+	if (!obsChip->process || !obsChip->file_exists || !obsChip->data_exists) { continue; }
+
+	// set the chip astrometry using the astrom file
+	pmChip *refChip = pmFPAviewThisChip (view, astrom->fpa);
+
+	psRegion *region = pmChipPixels (obsChip);
+	psPlane ptCP, ptFP;
+
+	ptCP.x = region->x0; ptCP.y = region->y0;
+	psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
+	xObs->data.F32[nPts] = ptFP.x;
+	yObs->data.F32[nPts] = ptFP.y;
+	psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
+	xRef->data.F32[nPts] = ptFP.x;
+	yRef->data.F32[nPts] = ptFP.y;
+	nPts ++;
+
+	ptCP.x = region->x0; ptCP.y = region->y1;
+	psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
+	xObs->data.F32[nPts] = ptFP.x;
+	yObs->data.F32[nPts] = ptFP.y;
+	psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
+	xRef->data.F32[nPts] = ptFP.x;
+	yRef->data.F32[nPts] = ptFP.y;
+	nPts ++;
+
+	ptCP.x = region->x1; ptCP.y = region->y1;
+	psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
+	xObs->data.F32[nPts] = ptFP.x;
+	yObs->data.F32[nPts] = ptFP.y;
+	psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
+	xRef->data.F32[nPts] = ptFP.x;
+	yRef->data.F32[nPts] = ptFP.y;
+	nPts ++;
+
+	ptCP.x = region->x1; ptCP.y = region->y0;
+	psPlaneTransformApply (&ptFP, obsChip->toFPA, &ptCP);
+	xObs->data.F32[nPts] = ptFP.x;
+	yObs->data.F32[nPts] = ptFP.y;
+	psPlaneTransformApply (&ptFP, refChip->toFPA, &ptCP);
+	xRef->data.F32[nPts] = ptFP.x;
+	yRef->data.F32[nPts] = ptFP.y;
+	nPts ++;
+
+	psFree (region);
+    }
+    xObs->n = yObs->n = xRef->n = yRef->n = nPts;
 	
-  psPlaneTransform *map = psPlaneTransformAlloc (1, 1);
+    psPlaneTransform *map = psPlaneTransformAlloc (1, 1);
   
-  psVector *mask = psVectorAlloc (nPts, PS_TYPE_U8);
-  psVectorInit (mask, 0);
-
-  psStats *stats = psStatsAlloc (PS_STAT_CLIPPED_MEAN | PS_STAT_CLIPPED_STDEV);
-  stats->clipIter = 1;
-
-  for (int i = 0; i < 3; i++) {
-      psVectorClipFitPolynomial2D (map->x, stats, mask, 0xff, xObs, NULL, xRef, yRef);
-      psTrace ("psModules.astrom", 3, "x resid: %f +/- %f (%ld of %ld)\n", stats->clippedMean, stats->clippedStdev, stats->clippedNvalues, xObs->n);
-
-      psVectorClipFitPolynomial2D (map->y, stats, mask, 0xff, yObs, NULL, xRef, yRef);
-      psTrace ("psModules.astrom", 3, "x resid: %f +/- %f (%ld of %ld)\n", stats->clippedMean, stats->clippedStdev, stats->clippedNvalues, yObs->n);
-  }
-
-  // loop over all chips, select the outliers, and replace the measured astrometry with the model
-  // the measured transformation above must be applied to make the comparison, and also then applied to the 
-  // model transformation
-
-  psFree (xObs);
-  psFree (yObs);
-  psFree (xRef);
-  psFree (yRef);
-  psFree (mask);
-  psFree (stats);
-
-  psFree (view);
-  view = pmFPAviewAlloc (0);
-
-  while ((obsChip = pmFPAviewNextChip (view, input->fpa, 1)) != NULL) {
-    psTrace ("psastro", 4, "Chip %d: %x %x\n", view->chip, obsChip->file_exists, obsChip->process);
-    if (!obsChip->process || !obsChip->file_exists || !obsChip->data_exists) { continue; }
-
-    // set the chip astrometry using the astrom file
-    pmChip *refChip = pmFPAviewThisChip (view, astrom->fpa);
-
-    // bad Astrometry test:  ref pixel or angle outside nominal
-
-    psPlane refPixel = {0.0, 0.0, 0.0, 0.0};
-    psPlane obsCoord, refCoord, tmpCoord;
-
-    // find location of 0,0 pixel in focal plane coords for this chip
-    psPlaneTransformApply (&obsCoord, obsChip->toFPA, &refPixel);
-
-    // find location of 0,0 pixel in focal plane coords for ref chip
-    // apply the global field rotation and offset before comparing
-    psPlaneTransformApply (&tmpCoord, refChip->toFPA, &refPixel);
-    psPlaneTransformApply (&refCoord, map, &tmpCoord);
+    psVector *mask = psVectorAlloc (nPts, PS_TYPE_U8);
+    psVectorInit (mask, 0);
+
+    psStats *stats = psStatsAlloc (PS_STAT_CLIPPED_MEAN | PS_STAT_CLIPPED_STDEV);
+    stats->clipIter = 1;
+
+    for (int i = 0; i < 3; i++) {
+	psVectorClipFitPolynomial2D (map->x, stats, mask, 0xff, xObs, NULL, xRef, yRef);
+	psTrace ("psModules.astrom", 3, "x resid: %f +/- %f (%ld of %ld)\n", stats->clippedMean, stats->clippedStdev, stats->clippedNvalues, xObs->n);
+
+	psVectorClipFitPolynomial2D (map->y, stats, mask, 0xff, yObs, NULL, xRef, yRef);
+	psTrace ("psModules.astrom", 3, "x resid: %f +/- %f (%ld of %ld)\n", stats->clippedMean, stats->clippedStdev, stats->clippedNvalues, yObs->n);
+    }
+
+    // loop over all chips, select the outliers, and replace the measured astrometry with the model
+    // the measured transformation above must be applied to make the comparison, and also then applied to the 
+    // model transformation
+
+    psFree (xObs);
+    psFree (yObs);
+    psFree (xRef);
+    psFree (yRef);
+    psFree (mask);
+    psFree (stats);
+
+    psFree (view);
+    view = pmFPAviewAlloc (0);
+
+    while ((obsChip = pmFPAviewNextChip (view, input->fpa, 1)) != NULL) {
+	psTrace ("psastro", 4, "Chip %d: %x %x\n", view->chip, obsChip->file_exists, obsChip->process);
+	if (!obsChip->process || !obsChip->file_exists || !obsChip->data_exists) { continue; }
+
+	// set the chip astrometry using the astrom file
+	pmChip *refChip = pmFPAviewThisChip (view, astrom->fpa);
+
+	// bad Astrometry test:  ref pixel or angle outside nominal
+
+	psPlane refPixel = {0.0, 0.0, 0.0, 0.0};
+	psPlane obsCoord, refCoord, tmpCoord;
+
+	// find location of 0,0 pixel in focal plane coords for this chip
+	psPlaneTransformApply (&obsCoord, obsChip->toFPA, &refPixel);
+
+	// find location of 0,0 pixel in focal plane coords for ref chip
+	// apply the global field rotation and offset before comparing
+	psPlaneTransformApply (&tmpCoord, refChip->toFPA, &refPixel);
+	psPlaneTransformApply (&refCoord, map, &tmpCoord);
     
-    psPlane offPixel = {100.0, 0.0, 100.0, 0.0};
-    psPlane obsOffPt, refOffPt;
-
-    // find location of 0,0 pixel in focal plane coords for this chip
-    psPlaneTransformApply (&obsOffPt, obsChip->toFPA, &offPixel);
-
-    // find location of 0,0 pixel in focal plane coords for ref chip
-    psPlaneTransformApply (&tmpCoord, refChip->toFPA, &offPixel);
-    psPlaneTransformApply (&refOffPt, map, &tmpCoord);
+	psPlane offPixel = {100.0, 0.0, 100.0, 0.0};
+	psPlane obsOffPt, refOffPt;
+
+	// find location of 0,0 pixel in focal plane coords for this chip
+	psPlaneTransformApply (&obsOffPt, obsChip->toFPA, &offPixel);
+
+	// find location of 0,0 pixel in focal plane coords for ref chip
+	psPlaneTransformApply (&tmpCoord, refChip->toFPA, &offPixel);
+	psPlaneTransformApply (&refOffPt, map, &tmpCoord);
     
-    double obsAngle = PM_DEG_RAD*atan2 (obsOffPt.y - obsCoord.y, obsOffPt.x - obsCoord.x);
-    double refAngle = PM_DEG_RAD*atan2 (refOffPt.y - refCoord.y, refOffPt.x - refCoord.x);
-
-    bool badAstrom = false;
-    badAstrom |= fabs(obsCoord.x - refCoord.x) > pixelTol;
-    badAstrom |= fabs(obsCoord.y - refCoord.y) > pixelTol;
-    badAstrom |= fabs(obsAngle   - refAngle)   > angleTol;
-
-    fprintf (stderr, "chip %d, angle: %f, pixel: %f,%f\n", view->chip, obsAngle - refAngle, obsCoord.x - refCoord.x, obsCoord.y - refCoord.y);
-
-    if (!badAstrom) continue;
-
-    psLogMsg ("psastro", PS_LOG_INFO, "fixing chip %d, angle: %f, pixel: %f,%f\n",
-	      view->chip, obsAngle - refAngle, obsCoord.x - refCoord.x, obsCoord.y - refCoord.y);
-
-    psFree (obsChip->toFPA);
-    psFree (obsChip->fromFPA);
-
-    // apply the exiting fromTPA transformation to make the new toFPA consistent with the toTPA layter
-    // XXX this only works if toTPA is at most a linear transformation
-    psPlaneTransform *toFPA = psPlaneTransformAlloc(refChip->toFPA->x->nX, refChip->toFPA->x->nY);
-    for (int i = 0; i <= refChip->toFPA->x->nX; i++) {
-	for (int j = 0; j <= refChip->toFPA->x->nY; j++) {
-	    double f1 = refChip->toFPA->x->coeffMask[i][j] ? 0.0 : map->x->coeff[1][0]*refChip->toFPA->x->coeff[i][j];
-	    double f2 = refChip->toFPA->y->coeffMask[i][j] ? 0.0 : map->x->coeff[0][1]*refChip->toFPA->y->coeff[i][j];
-	    toFPA->x->coeff[i][j] = f1 + f2;
-
-	    double g1 = refChip->toFPA->x->coeffMask[i][j] ? 0.0 : map->y->coeff[1][0]*refChip->toFPA->x->coeff[i][j];
-	    double g2 = refChip->toFPA->y->coeffMask[i][j] ? 0.0 : map->y->coeff[0][1]*refChip->toFPA->y->coeff[i][j];
-	    toFPA->y->coeff[i][j] = g1 + g2;
+	double obsAngle = PM_DEG_RAD*atan2 (obsOffPt.y - obsCoord.y, obsOffPt.x - obsCoord.x);
+	double refAngle = PM_DEG_RAD*atan2 (refOffPt.y - refCoord.y, refOffPt.x - refCoord.x);
+
+	bool badAstrom = false;
+	badAstrom |= fabs(obsCoord.x - refCoord.x) > pixelTol;
+	badAstrom |= fabs(obsCoord.y - refCoord.y) > pixelTol;
+	badAstrom |= fabs(obsAngle   - refAngle)   > angleTol;
+
+	fprintf (stderr, "chip %d, angle: %f, pixel: %f,%f\n", view->chip, obsAngle - refAngle, obsCoord.x - refCoord.x, obsCoord.y - refCoord.y);
+
+	// XXX for now, just use first readout
+	pmCell *cell = obsChip->cells->data[0];
+	pmReadout *readout = cell->readouts->data[0];
+
+	// update the header (pull or create local view to entry on readout->analysis)
+	psMetadata *updates = psMetadataLookupMetadata (&status, readout->analysis, "PSASTRO.HEADER");
+	if (!updates) {
+	    updates = psMetadataAlloc ();
+	    psMetadataAddMetadata (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_META_REPLACE, "psastro header stats", updates);
+	    psFree (updates);
 	}
-    }
-    toFPA->x->coeff[0][0] += map->x->coeff[0][0];
-    toFPA->y->coeff[0][0] += map->y->coeff[0][0];
-
-    psRegion *region = pmChipPixels (obsChip);
-    obsChip->toFPA   = toFPA;
-    obsChip->fromFPA = psPlaneTransformInvert(NULL, obsChip->toFPA, *region, 50);
-    psFree (region);
+
+	psMetadataAddF32 (updates, PS_LIST_TAIL, "AST_DX", PS_META_REPLACE, "chip x offset wrt model", obsCoord.x - refCoord.x);
+	psMetadataAddF32 (updates, PS_LIST_TAIL, "AST_DY", PS_META_REPLACE, "chip y offset wrt model", obsCoord.y - refCoord.y);
+	psMetadataAddF32 (updates, PS_LIST_TAIL, "AST_DT", PS_META_REPLACE, "chip rot offset wrt model", obsAngle - refAngle);
+
+	// for successful chips, save the measured offsets in the header
+	if (!badAstrom) continue;
+
+	psLogMsg ("psastro", PS_LOG_INFO, "fixing chip %d, angle: %f, pixel: %f,%f\n",
+		  view->chip, obsAngle - refAngle, obsCoord.x - refCoord.x, obsCoord.y - refCoord.y);
+
+	psFree (obsChip->toFPA);
+	psFree (obsChip->fromFPA);
+
+	// apply the exiting fromTPA transformation to make the new toFPA consistent with the toTPA layter
+	// XXX this only works if toTPA is at most a linear transformation
+	psPlaneTransform *toFPA = psPlaneTransformAlloc(refChip->toFPA->x->nX, refChip->toFPA->x->nY);
+	for (int i = 0; i <= refChip->toFPA->x->nX; i++) {
+	    for (int j = 0; j <= refChip->toFPA->x->nY; j++) {
+		double f1 = refChip->toFPA->x->coeffMask[i][j] ? 0.0 : map->x->coeff[1][0]*refChip->toFPA->x->coeff[i][j];
+		double f2 = refChip->toFPA->y->coeffMask[i][j] ? 0.0 : map->x->coeff[0][1]*refChip->toFPA->y->coeff[i][j];
+		toFPA->x->coeff[i][j] = f1 + f2;
+
+		double g1 = refChip->toFPA->x->coeffMask[i][j] ? 0.0 : map->y->coeff[1][0]*refChip->toFPA->x->coeff[i][j];
+		double g2 = refChip->toFPA->y->coeffMask[i][j] ? 0.0 : map->y->coeff[0][1]*refChip->toFPA->y->coeff[i][j];
+		toFPA->y->coeff[i][j] = g1 + g2;
+	    }
+	}
+	toFPA->x->coeff[0][0] += map->x->coeff[0][0];
+	toFPA->y->coeff[0][0] += map->y->coeff[0][0];
+
+	psRegion *region = pmChipPixels (obsChip);
+	obsChip->toFPA   = toFPA;
+	obsChip->fromFPA = psPlaneTransformInvert(NULL, obsChip->toFPA, *region, 50);
+	psFree (region);
     
-    // XXX this stuff below should be applied to each readout...
-    // XXX for now, just use first readout
-    pmCell *cell = obsChip->cells->data[0];
-    pmReadout *readout = cell->readouts->data[0];
-
-    // use the new position to re-try the match fit
-    // select the raw objects for this readout
-    psArray *rawstars = psMetadataLookupPtr (NULL, readout->analysis, "PSASTRO.RAWSTARS");
-    if (rawstars == NULL) { continue; }
-
-    // select the raw objects for this readout
-    psArray *refstars = psMetadataLookupPtr (NULL, readout->analysis, "PSASTRO.REFSTARS");
-    if (refstars == NULL) { continue; }
-
-    // the absolute minimum number of stars is 4 (for order = 1)
-    if ((rawstars->n < 4) || (refstars->n < 4)) {
-	readout->data_exists = false;
-	psLogMsg ("psastro", 3, "insufficient rawstars (%ld) or refstars (%ld)", 
-		  rawstars->n, refstars->n);
-	continue;
-    } 
-
-    psastroUpdateChipToFPA (input->fpa, obsChip, rawstars, refstars);
-
-    // update the header
-    psMetadata *updates = psMemIncrRefCounter (psMetadataLookupMetadata (&status, readout->analysis, "PSASTRO.HEADER"));
-    if (!updates) {
-	updates = psMetadataAlloc ();
-    }
-
-    // XXX update the header with info to reflect the failure
-    if (!psastroOneChipFit (input->fpa, obsChip, refstars, rawstars, recipe, updates)) {
-	readout->data_exists = false;
-	psLogMsg ("psastro", 3, "failed to find a solution\n");
-	psFree (updates);
-	continue;
-    }
-
-    pmAstromWriteWCS (updates, input->fpa, obsChip, NONLIN_TOL);
-    psMetadataAdd (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_META_REPLACE | PS_DATA_METADATA, "psastro header stats", updates);
-    psFree (updates);
-  }
-
-  psFree (map);
-  psFree (view);
-  return true;
+	// use the new position to re-try the match fit
+	// select the raw objects for this readout
+	psArray *rawstars = psMetadataLookupPtr (NULL, readout->analysis, "PSASTRO.RAWSTARS");
+	if (rawstars == NULL) { continue; }
+
+	// select the raw objects for this readout
+	psArray *refstars = psMetadataLookupPtr (NULL, readout->analysis, "PSASTRO.REFSTARS");
+	if (refstars == NULL) { continue; }
+
+	// the absolute minimum number of stars is 4 (for order = 1)
+	if ((rawstars->n < 4) || (refstars->n < 4)) {
+	    readout->data_exists = false;
+	    psLogMsg ("psastro", 3, "insufficient rawstars (%ld) or refstars (%ld)", 
+		      rawstars->n, refstars->n);
+	    continue;
+	} 
+
+	psastroUpdateChipToFPA (input->fpa, obsChip, rawstars, refstars);
+
+	// XXX update the header with info to reflect the failure
+	if (!psastroOneChipFit (input->fpa, obsChip, refstars, rawstars, recipe, updates)) {
+	    readout->data_exists = false;
+	    psLogMsg ("psastro", 3, "failed to find a solution\n");
+	    continue;
+	}
+
+	pmAstromWriteWCS (updates, input->fpa, obsChip, NONLIN_TOL);
+    }
+
+    psFree (map);
+    psFree (view);
+    return true;
 }
Index: /trunk/psastro/src/psastroFixChipsTest.c
===================================================================
--- /trunk/psastro/src/psastroFixChipsTest.c	(revision 20270)
+++ /trunk/psastro/src/psastroFixChipsTest.c	(revision 20271)
@@ -201,5 +201,11 @@
 
 	// save WCS and analysis metadata in update header
-	psMetadata *updates = psMetadataAlloc();
+	// (pull or create local view to entry on readout->analysis)
+	psMetadata *updates = psMetadataLookupMetadata (&status, readout->analysis, "PSASTRO.HEADER");
+	if (!updates) {
+	    updates = psMetadataAlloc ();
+	    psMetadataAddMetadata (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_META_REPLACE, "psastro header stats", updates);
+	    psFree (updates);
+	}
 
 	// select the raw objects for this readout
@@ -228,12 +234,8 @@
 	    readout->data_exists = false;
 	    psLogMsg ("psastro", 3, "failed to find a solution\n");
-	    psFree (updates);
 	    continue;
 	}
 
 	pmAstromWriteWCS (updates, fpa, chip, NONLIN_TOL);
-	psMetadataAdd (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_DATA_METADATA, "psastro header stats", updates);
-	psFree (updates);
-
     }