diff --git a/LibSidServo/sidservo.h b/LibSidServo/sidservo.h
index 21d32ce..ac04f9f 100644
--- a/LibSidServo/sidservo.h
+++ b/LibSidServo/sidservo.h
@@ -206,7 +206,7 @@ typedef struct{
     // TODO: change (or add flags) switching slew-and-stop and slew-and-track
     // add mount state: stop/slew/guide
     mcc_errcodes_t  (*slewTo)(const coordpair_t *target, slewflags_t flags);
-    mcc_errcodes_t  (*correctBy)(coordpair_t *delta); // delta = Target - Real
+    mcc_errcodes_t  (*correctTo)(coordval_pair_t *target);
     mcc_errcodes_t  (*moveTo)(const coordpair_t *target); // move to given position and stop
     mcc_errcodes_t  (*moveWspeed)(const coordpair_t *target, const  coordpair_t *speed); // move with given max speed
     mcc_errcodes_t  (*setSpeed)(const coordpair_t *tagspeed); // set speed