diff --git a/geopack/src/Modif.for b/geopack/src/Modif.for
index d7a8198..7903911 100644
--- a/geopack/src/Modif.for
+++ b/geopack/src/Modif.for
@@ -19,3 +19,16 @@
       CALL T96_01 (IOPT,PARMOD,PSI,X,Y,Z,BX,BY,BZ)
 
       END
+
+      SUBROUTINE RECALC_08_MODIFIED (IYEAR,IDAY,IHOUR,MIN,ISEC,VGSEX,
+     * VGSEY,VGSEZ,TILT_out)
+    
+      EXTERNAL RECALC_08
+
+      COMMON /GEOPACK1/ PSI
+
+      CALL RECALC_08 (IYEAR,IDAY,IHOUR,MIN,ISEC,VGSEX,VGSEY,VGSEZ)
+
+      TILT_out = PSI
+
+      END
diff --git a/geopack/src/include/geopack.hh b/geopack/src/include/geopack.hh
index 5ddecc0..b7dd8b1 100644
--- a/geopack/src/include/geopack.hh
+++ b/geopack/src/include/geopack.hh
@@ -7,6 +7,9 @@ extern "C" {
 
     void recalc_08_(int* iyr, int *iday, int* ihour, int* min, int* isec,
         float* V_GSE_X_i, float* V_GSE_Y_i, float* V_GSE_Z_i);
+
+    void recalc_08_modified_(int* iyr, int *iday, int* ihour, int* min, int* isec,
+        float* V_GSE_X_i, float* V_GSE_Y_i, float* V_GSE_Z_i, float* PSI);
     
     void gswgse_08_(float* sat_pos_GSW_X_i, float* sat_pos_GSW_Y_i, float* sat_pos_GSW_Z_i, 
         float* sat_pos_GSE_X_i, float* sat_pos_GSE_Y_i, float* sat_pos_GSE_Z_i, int* transform_flag);
--
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