Index: trunk/psastro/src/psastroModelAnalysis.c
===================================================================
--- trunk/psastro/src/psastroModelAnalysis.c	(revision 19309)
+++ trunk/psastro/src/psastroModelAnalysis.c	(revision 19386)
@@ -14,4 +14,7 @@
     pmFPAfile *output = psMetadataLookupPtr (&status, config->files, "PSASTRO.OUT.MODEL");
     if (!status) psAbort ("Can't find output pmFPAfile PSASTRO.OUT.MODEL");
+
+    char *outroot = psMetadataLookupStr (&status, config->arguments, "OUTPUT");
+    if (!status || !outroot) psAbort ("Can't find outroot on config->arguments");
 
     // physical pixel scale in microns per pixel
@@ -58,4 +61,14 @@
     output->fpa = NULL;
 
+    char filename[256];
+    snprintf (filename, 256, "%s.bore", outroot);
+    FILE *outfile = fopen (filename, "w");
+    if (!outfile) {
+        psError(PSASTRO_ERR_ARGUMENTS, true, "cannot open %s for output", filename);
+	return false;
+    }
+
+    float posBoundary = 0.0;
+
     // extract the relevant measured and reported values from the reference chip
     for (int i = 0; i < files->n; i++) {
@@ -80,13 +93,20 @@
 
 	// we have two measurements of the posangle (may be parity flipped to different quadrants)
+	// atan2 returns values in the range 0-2pi
+	// all posZero values should be clustered in some region, but we need to flip over the 0,360 boundary correctly.
+	// push all to one side or the other
 	float posangle = PM_DEG_RAD * atan2 (chip->toFPA->y->coeff[1][0], chip->toFPA->x->coeff[1][0]);
 	posZero->data.F32[n] = POSANGLE - posangle;
-	while (posZero->data.F32[n] > 360.0) posZero->data.F32[n] -= 360.0;
-	while (posZero->data.F32[n] <   0.0) posZero->data.F32[n] += 360.0;
+	if (n == 0) {
+	    posBoundary = posZero->data.F32[n] + 180.0;
+	} else {
+	    while (posZero->data.F32[n] > posBoundary) posZero->data.F32[n] -= 360.0;
+	    while (posZero->data.F32[n] < posBoundary - 360.0) posZero->data.F32[n] += 360.0;
+	}
 
 	Po->data.F32[n] = POSANGLE * PM_RAD_DEG; // reported position angle
 	Xo->data.F32[n] = chip->fromFPA->x->coeff[0][0]; // reported boresite x position in ref chip coordinates
 	Yo->data.F32[n] = chip->fromFPA->y->coeff[0][0]; // reported boresite y position in ref chip coordinates
-	fprintf (stderr, "%d : %f %f : %f = %f - %f\n", i, Xo->data.F32[n], Yo->data.F32[n], posZero->data.F32[n], POSANGLE, posangle);
+	fprintf (outfile, "%d : %f %f : %f = %f - %f\n", i, Xo->data.F32[n], Yo->data.F32[n], posZero->data.F32[n], POSANGLE, posangle);
 	n ++;
     }
@@ -100,9 +120,11 @@
     psVectorStats (stats, posZero, NULL, NULL, 0);
 
-    fprintf (stderr, "pos zero %f +/- %f\n", stats->sampleMedian, stats->sampleStdev);
+    fprintf (outfile, "# pos zero %f +/- %f\n", stats->sampleMedian, stats->sampleStdev);
     psMetadataAddF32 (output->fpa->concepts, PS_LIST_TAIL, "FPA.POS_ZERO", PS_META_REPLACE, "offset between obs and meas posangle", stats->sampleMedian); 
+    fclose (outfile);
 
-    psVector *params = psastroModelFitBoresite (Xo, Yo, Po);
+    psVector *params = psastroModelFitBoresite (Xo, Yo, Po, outroot);
     if (params->n != 6) psAbort ("error");
+
 
     psMetadataAddF32 (output->fpa->concepts, PS_LIST_TAIL, "FPA.BORE.X0", PS_META_REPLACE, "boresite parameter", params->data.F32[PAR_X0]);