Index: celengine/observer.h
===================================================================
--- celengine/observer.h	(revision 4137)
+++ celengine/observer.h	(working copy)
@@ -52,6 +52,7 @@
                   const Selection& _refObject,
                   const Selection& _targetObj = Selection());
     ObserverFrame(const ObserverFrame&);
+    ObserverFrame(const ReferenceFrame& f);
     
     ~ObserverFrame();
     
@@ -84,7 +85,7 @@
     
 private:
     CoordinateSystem coordSys;
-    ReferenceFrame* frame;
+    const ReferenceFrame* frame;
     Selection targetObject;
 };
 
Index: celengine/observer.cpp
===================================================================
--- celengine/observer.cpp	(revision 4137)
+++ celengine/observer.cpp	(working copy)
@@ -1416,6 +1416,10 @@
 }
 
 
+/*! Create a new frame with the specified coordinate system and
+ *  reference object. The targetObject is only needed for phase
+ *  lock frames; the argument is ignored for other frames.
+ */
 ObserverFrame::ObserverFrame(CoordinateSystem _coordSys,
                              const Selection& _refObject,
                              const Selection& _targetObject) :
@@ -1428,6 +1432,18 @@
 }
 
 
+/*! Create a new ObserverFrame with the specified reference frame.
+ *  The coordinate system of this frame will be marked as unknown.
+ */
+ObserverFrame::ObserverFrame(const ReferenceFrame &f) :
+    coordSys(Unknown),
+    frame(&f)
+{
+    frame->addRef();
+}
+
+
+/*! Copy constructor. */
 ObserverFrame::ObserverFrame(const ObserverFrame& f) :
     coordSys(f.coordSys),
     frame(f.frame),
Index: celestia/celx.cpp
===================================================================
--- celestia/celx.cpp	(revision 4137)
+++ celestia/celx.cpp	(working copy)
@@ -3135,6 +3135,125 @@
 }
 
 
+/*! object:bodyfixedframe()
+ *
+ * Return the body-fixed frame for this object.
+ *
+ * Example: get the body-fixed frame of the Earth
+ * --
+ * earth = celestia:find("Sol/Earth")
+ * ebf = earth:bodyfixedframe()
+ *
+ */
+static int object_bodyfixedframe(lua_State* l)
+{
+	checkArgs(l, 1, 1, "No arguments allowed for to object:bodyfixedframe");
+
+	Selection* sel = this_object(l);    
+    frame_new(l, ObserverFrame(ObserverFrame::BodyFixed, *sel));
+    
+    return 1;
+}
+    
+
+/*! object:equatorialframe()
+ *
+ * Return the mean equatorial frame for this object.
+ *
+ * Example: get the equatorial frame of the Earth
+ * --
+ * earth = celestia:find("Sol/Earth")
+ * eme = earth:equatorialframe()
+ *
+ */
+static int object_equatorialframe(lua_State* l)
+{
+    // TODO: allow one argument specifying a freeze time
+	checkArgs(l, 1, 1, "No arguments allowed for to object:equatorialframe");
+    
+	Selection* sel = this_object(l);    
+    frame_new(l, ObserverFrame(ObserverFrame::Equatorial, *sel));
+    
+    return 1;
+}
+
+
+/*! object:orbitframe(time: t)
+ *
+ * Return the frame in which the orbit for an object is defined at a particular
+ * time. If time isn't specified, the current simulation time is assumed. The
+ * positions of stars and deep sky objects are always defined in the universal
+ * frame.
+ *
+ * Example: get the orbital frame for the Earth at the current time.
+ * --
+ * earth = celestia:find("Sol/Earth")
+ * eof = earth:orbitframe() 
+ *
+ */
+static int object_orbitframe(lua_State* l)
+{
+	checkArgs(l, 1, 2, "One or no arguments allowed for to object:orbitframe");
+        
+	Selection* sel = this_object(l);
+    CelestiaCore* appCore = getAppCore(l, AllErrors);
+    
+    double t = safeGetNumber(l, 2, WrongType, "Time expected as argument to object:orbitframe",
+                             appCore->getSimulation()->getTime());
+    
+    if (sel->body() == NULL)
+    {
+        // The default universal frame
+        frame_new(l, ObserverFrame());
+    }
+    else 
+    {
+        const ReferenceFrame* f = sel->body()->getOrbitFrame(t);
+        frame_new(l, ObserverFrame(*f));
+    }
+    
+    return 1;
+}
+
+
+/*! object:bodyframe(time: t)
+*
+* Return the frame in which the orientation for an object is defined at a 
+* particular time. If time isn't specified, the current simulation time is
+* assumed. The positions of stars and deep sky objects are always defined
+* in the universal frame.
+*
+* Example: get the curren body frame for the International Space Station.
+* --
+* iss = celestia:find("Sol/Earth/ISS")
+* f = iss:bodyframe() 
+*
+*/
+static int object_bodyframe(lua_State* l)
+{
+	checkArgs(l, 1, 2, "One or no arguments allowed for to object:bodyframe");
+    
+	Selection* sel = this_object(l);
+    CelestiaCore* appCore = getAppCore(l, AllErrors);
+    
+    double t = safeGetNumber(l, 2, WrongType, "Time expected as argument to object:orbitframe",
+                             appCore->getSimulation()->getTime());
+    
+    if (sel->body() == NULL)
+    {
+        // The default universal frame
+        frame_new(l, ObserverFrame());
+    }
+    else 
+    {
+        const ReferenceFrame* f = sel->body()->getBodyFrame(t);
+        frame_new(l, ObserverFrame(*f));
+    }
+    
+    return 1;
+}
+
+
 static void CreateObjectMetaTable(lua_State* l)
 {
     CreateClassMetatable(l, _Object);
@@ -3152,7 +3271,7 @@
     RegisterMethod(l, "type", object_type);
     RegisterMethod(l, "spectraltype", object_spectraltype);
     RegisterMethod(l, "getinfo", object_getinfo);
-	RegisterMethod(l, "catalognumber", object_catalognumber);
+    RegisterMethod(l, "catalognumber", object_catalognumber);
     RegisterMethod(l, "absmag", object_absmag);
     RegisterMethod(l, "name", object_name);
     RegisterMethod(l, "localname", object_localname);
@@ -3161,6 +3280,10 @@
     RegisterMethod(l, "getposition", object_getposition);
     RegisterMethod(l, "getchildren", object_getchildren);
     RegisterMethod(l, "locations", object_locations);
+    RegisterMethod(l, "bodyfixedframe", object_bodyfixedframe);
+    RegisterMethod(l, "equatorialframe", object_equatorialframe);
+    RegisterMethod(l, "orbitframe", object_orbitframe);
+    RegisterMethod(l, "bodyframe", object_bodyframe);
     RegisterMethod(l, "preloadtexture", object_preloadtexture);
 
     lua_pop(l, 1); // pop metatable off the stack