Changeset 33604

Timestamp:

Mar 24, 2012, 3:16:42 PM (14 years ago)

Author:

eugene

Message:

add w-band color-correction from r: this is very sketchy

File:

• branches/eam_branches/ipp-20111122/psastro/src/psastroLoadRefstars.c (modified) (1 diff)

branches/eam_branches/ipp-20111122/psastro/src/psastroLoadRefstars.c

@@ -174 +174 @@
     }
 
+    // apply a color correction
+    {
+        // from Tonry 
+        // (w-r)_obs = 0.042 + 0.166 (r-i)_obs - 0.398 (r-i)_obs^2,  (r-i)_obs < 0.5
+        // (w-r)_obs = 0.268 - 0.435 (r-i)_obs - 0.078 (r-i)_obs^2,  (r-i)_obs > 0.5
+        // thus, for (r-i < 0.5):
+        // (r - i < 0.5) : w = r + 0.042 + 0.166*(r-i) - 0.398(r-i)^2
+        // (r - i > 0.5) : w = r + 0.268 - 0.435 (r-i) - 0.078(r-i)^2
+
+        // apply a color correction
+        // XXX this is very GPC1 specific and hard-wired -- be very afraid!
+        if (!strcmp(photcode, "w")) {
+            for (int i = 0; i < refstars->n; i++) {
+                pmAstromObj *ref = refstars->data[i];
+                float r = ref->Mag;
+                float ri = ref->Color;
+                // saturate at some valid range limits
+                ri = PS_MAX (PS_MIN(r, 2.0), -0.2);
+                float w = NAN;
+                if (ri < 0.5) {
+                    w = r + 0.042 + 0.166*(ri) - 0.398*PS_SQR(ri);
+                } else {
+                    w = r + 0.268 - 0.435*(ri) - 0.078*PS_SQR(ri);
+                }
+                ref->Mag = w;
+            }
+        }
+    }
+
     psLogMsg ("psastro", 3, "loaded %ld reference stars : %f sec\n", refstars->n, psTimerMark ("psastro"));