diff --git a/simgear/scene/util/OrthophotoManager.cxx b/simgear/scene/util/OrthophotoManager.cxx
index 14667613..3a3ce9c8 100644
--- a/simgear/scene/util/OrthophotoManager.cxx
+++ b/simgear/scene/util/OrthophotoManager.cxx
@@ -347,9 +347,9 @@ namespace simgear {
     }
 
     void OrthophotoManager::registerOrthophoto(const long bucket_idx, const OrthophotoRef& orthophoto) {
-        OrthophotoRef& entry = _orthophotos[bucket_idx];
+        OrthophotoWeakRef& entry = _orthophotos[bucket_idx];
 
-        if (entry) {
+        if (entry.valid()) {
             SG_LOG(SG_TERRAIN, SG_WARN, "OrthophotoManager::registerOrthophoto(): Bucket index " << bucket_idx << " already has a registered orthophoto.");
         }
 
@@ -362,26 +362,13 @@ namespace simgear {
         SG_LOG(SG_TERRAIN, SG_INFO, "Registered orthophoto for bucket index " << bucket_idx);
     }
 
-    void OrthophotoManager::unregisterOrthophoto(const long bucket_idx) {
-        if (_orthophotos[bucket_idx]) {
-            _orthophotos.erase(bucket_idx);
-            SG_LOG(SG_TERRAIN, SG_INFO, "Unregistered orthophoto with bucket index " << bucket_idx);
-        } else {
-            SG_LOG(SG_TERRAIN, SG_WARN, "OrthophotoManager::unregisterOrthophoto(): Attempted to unregister orthophoto with bucket index that is not currently registered.");
-        }
-    }
-
-    void OrthophotoManager::unregisterAll() {
-        _orthophotos.clear();
-        SG_LOG(SG_TERRAIN, SG_INFO, "Unregistered all orthophotos");
-    }
-
     OrthophotoRef OrthophotoManager::getOrthophoto(const long bucket_idx) {
-        if (_orthophotos[bucket_idx]) {
-            return _orthophotos[bucket_idx];
-        } else {
-            return nullptr;
+        OrthophotoWeakRef weak_ref = _orthophotos[bucket_idx];
+        OrthophotoRef ref;
+        if (weak_ref.valid()) {
+            weak_ref.lock(ref);
         }
+        return ref;
     }
 
     OrthophotoRef OrthophotoManager::getOrthophoto(const std::vector<SGVec3d>& nodes, const SGVec3d& center) {
diff --git a/simgear/scene/util/OrthophotoManager.hxx b/simgear/scene/util/OrthophotoManager.hxx
index 950be9cf..752a4525 100644
--- a/simgear/scene/util/OrthophotoManager.hxx
+++ b/simgear/scene/util/OrthophotoManager.hxx
@@ -22,9 +22,11 @@
 
 #include <unordered_map>
 
-#include <osg/Referenced>
 #include <osg/Image>
 #include <osg/Texture2D>
+#include <osg/Referenced>
+#include <osg/ref_ptr>
+#include <osg/observer_ptr>
 #include <osgDB/ReaderWriter>
 #include <osgDB/ReadFile>
 #include <simgear/misc/sg_dir.hxx>
@@ -41,6 +43,7 @@ namespace simgear {
 
     class Orthophoto;
     using OrthophotoRef = osg::ref_ptr<Orthophoto>;
+    using OrthophotoWeakRef = osg::observer_ptr<Orthophoto>;
 
     class OrthophotoBounds {
     private:
@@ -85,13 +88,11 @@ namespace simgear {
 
     class OrthophotoManager : public osg::Referenced {
     private:
-        std::unordered_map<long, OrthophotoRef> _orthophotos;
+        std::unordered_map<long, OrthophotoWeakRef> _orthophotos;
     public:
         static OrthophotoManager* instance();
 
         void registerOrthophoto(const long bucket_idx, const OrthophotoRef& orthophoto);
-        void unregisterOrthophoto(const long bucket_idx);
-        void unregisterAll();
 
         /**
          * Get an orthophoto by bucket index