diff --git a/Meade.net.Telescope.UnitTests/TelescopeUnitTests.cs b/Meade.net.Telescope.UnitTests/TelescopeUnitTests.cs
index e483868..2a0403c 100644
--- a/Meade.net.Telescope.UnitTests/TelescopeUnitTests.cs
+++ b/Meade.net.Telescope.UnitTests/TelescopeUnitTests.cs
@@ -67,10 +67,10 @@ namespace Meade.net.Telescope.UnitTests
                 _sharedResourcesWrapperMock.Object, _astroMathsMock.Object);
         }
 
-        private void ConnectTelescope()
+        private void ConnectTelescope(string productName = TelescopeList.Autostar497, string firmwareVersion = TelescopeList.Autostar497_31Ee)
         {
-            _sharedResourcesWrapperMock.Setup(x => x.ProductName).Returns(() => TelescopeList.Autostar497);
-            _sharedResourcesWrapperMock.Setup(x => x.FirmwareVersion).Returns(() => TelescopeList.Autostar497_31Ee);
+            _sharedResourcesWrapperMock.Setup(x => x.ProductName).Returns(() => productName);
+            _sharedResourcesWrapperMock.Setup(x => x.FirmwareVersion).Returns(() => firmwareVersion);
             _telescope.Connected = true;
         }
 
@@ -2184,6 +2184,25 @@ namespace Meade.net.Telescope.UnitTests
             _sharedResourcesWrapperMock.Verify(x => x.SendString(":D#"),Times.Once);
         }
 
+        [TestCase(TelescopeList.LX200CLASSIC,"","|", true)]
+        [TestCase(TelescopeList.LX200CLASSIC, "", "||||||||", true)]
+        [TestCase(TelescopeList.LX200CLASSIC, "", "", false)]
+        [TestCase(TelescopeList.LX200CLASSIC, "", "[FF][FF][FF][FF][FF][FF][FF][FF][FF][FF][FF][FF][FF][FF]  [FF][FF][FF][FF][FF][FF]", false)]
+        [TestCase(TelescopeList.Autostar497, TelescopeList.Autostar497_43Eg, "|", true)]
+        [TestCase(TelescopeList.Autostar497, TelescopeList.Autostar497_43Eg, "", false)]
+        public void Slewing_WhenTelescopeNotSlewing_ThenReturnsFalse(string productName, string firmwareVersion, string response, bool isSlewing)
+        {
+            _sharedResourcesWrapperMock.Setup(x => x.SendString(":D#")).Returns(response);
+
+            ConnectTelescope(productName, firmwareVersion);
+
+            var result = _telescope.Slewing;
+
+            Assert.That(result, Is.EqualTo(isSlewing));
+
+            _sharedResourcesWrapperMock.Verify(x => x.SendString(":D#"), Times.Once);
+        }
+
         [TestCase(1, TelescopeAxes.axisPrimary)]
         [TestCase(-1, TelescopeAxes.axisPrimary)]
         [TestCase(1, TelescopeAxes.axisSecondary)]
diff --git a/Meade.net.Telescope/Telescope.cs b/Meade.net.Telescope/Telescope.cs
index 08d21f0..c208cc9 100644
--- a/Meade.net.Telescope/Telescope.cs
+++ b/Meade.net.Telescope/Telescope.cs
@@ -1883,9 +1883,9 @@ namespace ASCOM.Meade.net
             }
 
             var trimmedResult = result.Trim();
-            var isResultEmpty = trimmedResult != string.Empty;
+            var isResultEmpty = trimmedResult == string.Empty;
 
-            var isSlewing = isResultEmpty;
+            var isSlewing = !isResultEmpty;
 
             if (!isResultEmpty) //the LX-200 can return crap from the buffer when it's not slewing so let's try to filter that out.
             {
diff --git a/Meade.net/TelescopeList.cs b/Meade.net/TelescopeList.cs
index 61e4293..440c4bd 100644
--- a/Meade.net/TelescopeList.cs
+++ b/Meade.net/TelescopeList.cs
@@ -4,30 +4,30 @@
     {
         #region Autostar 497/Audiostar
 
-        public static readonly string Autostar497 = "Autostar";
+        public const string Autostar497 = "Autostar";
 
         //Autostar/Audiostar firmware revisions
         // ReSharper disable once InconsistentNaming
-        public static readonly string Autostar497_30Ee = "30Ee";
+        public const string Autostar497_30Ee = "30Ee";
         // ReSharper disable once InconsistentNaming
-        public static readonly string Autostar497_31Ee = "31Ee";
+        public const string Autostar497_31Ee = "31Ee";
         // ReSharper disable once InconsistentNaming
-        public static readonly string Autostar497_43Eg = "43Eg";
+        public const string Autostar497_43Eg = "43Eg";
 
         #endregion
 
         #region LX200GPS
 
         // ReSharper disable once InconsistentNaming
-        public static readonly string LX200GPS = "LX2001";
+        public const string LX200GPS = "LX2001";
 
         // ReSharper disable once InconsistentNaming
-        public static readonly string LX200GPS_42G = "4.2G";
+        public const string LX200GPS_42G = "4.2G";
         #endregion
 
         #region LX200EMC
         // ReSharper disable once InconsistentNaming
-        public static readonly string LX200CLASSIC = "LX200 Classic"; //GVP command is not supported!
+        public const string LX200CLASSIC = "LX200 Classic"; //GVP command is not supported!
         #endregion
     }
 }