fixed GC name in example

docs/notebooks/dr3-empirical-completeness.ipynb

@@ -6,7 +6,7 @@
    "source": [
     "# Empirical survey selection function for Gaia DR3\n",
     "\n",
-    "updated: 01 March 2023"
+    "updated: 09 Oct 2023"
    ]
   },
   {
@@ -136,9 +136,9 @@
    "source": [
     "You might recognise some features already. The stripes are caused by the Gaia scanning law. Regions with high stellar density are also visible, in the direction of the Galactic centre, or the Magellanic clouds. The presence of globular clusters is also visible, as individual healpixels of low completeness.\n",
     "\n",
-    "We can zoom in on a particular region with **gnomview**, for instance the globular cluster NGC 6752 near (ra,dec)=(288,-60).\n",
+    "We can zoom in on a particular region with **gnomview**, for instance the globular cluster Omega Cen (NGC 5139) near (ra,dec)=(200.5,-47.5).\n",
     "\n",
-    "To display a 2 degree x 2 degree field we make a plot with width of 240 pixels, and 0.5 arcminute per pixel."
+    "Let's make a plot with width of 480 pixels, and 0.5 arcminute per pixel."
    ]
   },
   {