Fixed typo and improved explanations

notebooks/explore_DL2.ipynb

@@ -32,7 +32,7 @@
     "The cuts (gammaness & theta2) used for computing significances are \"reasonable\" for a first attempt at source detection. The ones for the high-E subset are about optimal for sensitivity (at low zeniths, say below 40 deg, good observation conditions and a Crab-like spectrum). \n",
     "For low-energies it is hard to say what \"optimal cuts\" would be - that is quite dependent on the source energy spectrum, and also more sensitive to zenith angle (via the energy threshold). Do **not** play with the cuts on a yet-undetected source! If custom optimization of cuts is necessary, that can be done on simulations (for an assumed spectrum) or on a confirmed and bright source.\n",
     "\n",
-    "NOTE: the notebook is quite slow (due mainly to data loading and coordinate transformations) and memory-hungry, so you *may* have trouble with datasets longer than several tens of hours."
+    "NOTE: the notebook is quite slow (due mainly to data loading and coordinate transformations) and memory-hungry, so you *may* have trouble with datasets longer than several tens of hours. For very long datasets, if you have problems with this notebook, you can do the theta2 plots from DL3 FITS files (using Gammapy)."
    ]
   },
   {
@@ -95,7 +95,7 @@
     "    t_eff += lt\n",
     "    t_elapsed += et\n",
     "\n",
-    "    # Redue precision to save memory:\n",
+    "    # Reduce precision to save memory:\n",
     "    for colname in needed_columns:\n",
     "        if colname == 'dragon_time': # here we need float64, keep it.\n",
     "            continue\n",