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mcc/mcc_ccte_erfa.h

@@ -590,7 +590,18 @@ public:
 
         // the main scenario: from ICRS to apparent
         if (from_pt.pair_kind == MccCoordPairKind::COORDS_KIND_RADEC_ICRS) {
+            to_pt->RA_ICRS = from_pt.X;
+            to_pt->DEC_ICRS = from_pt.Y;
+
             return icrs2obs(from_pt, to_pt);
+        } else {  // from apparent (2025-12-18: according to addition of RA/DEC_OCRS to mcc_eqt_hrz_coord_c)
+            cpt.pair_kind = MccCoordPairKind::COORDS_KIND_RADEC_ICRS;
+            ret = transformCoordinates(from_pt, &cpt);  // to ICRS
+            if (!ret) {
+                ret = transformCoordinates(cpt, to_pt);
+            }
+
+            return ret;
         }
 
         // from apparent: copy corresponded coordinates and compute other ones (ignore to_pt->pair_kind)