diff --git a/docs/notebooks/apply_oe.ipynb b/docs/notebooks/apply_oe.ipynb
index 1b92228..95628db 100644
--- a/docs/notebooks/apply_oe.ipynb
+++ b/docs/notebooks/apply_oe.ipynb
@@ -39,7 +39,63 @@
     "\n",
     "`INPUT_RADIANCE` `INPUT_LOC` `INPUT_OBS` `WORKING_DIRECTORY` `SENSOR` and `--surface_path`.\n",
     "\n",
-    "which must be entered in the specified order (except `--surface_path` which can be added at any point but still required). Descriptions of each are found in the docstring printed above. It is important to note that the `INPUT_RADIANCE`, `INPUT_LOC`, and `INPUT_OBS` are ENVI raster data formats that must be at the same row-column dimensions. The `--surface_path` points Isofit torwards the constructed prior distribution file for surface reflectance. Optional arguments are denoted by the '--' in their name, e.g.  `--modtran_path`, `--pressure_elevation`. It is important to note that the default radiative transfer engine (RTE) is currently set to Modtran. You must specify an `--emulator_path` without a Modtran installation."
+    "which must be entered in the specified order (except `--surface_path` which can be added at any point but still required). Descriptions of each are found in the docstring printed above. It is important to note that the `INPUT_RADIANCE`, `INPUT_LOC`, and `INPUT_OBS` are ENVI raster data formats that must be at the same row-column dimensions. The `--surface_path` points Isofit towards the constructed prior distribution file for surface reflectance. Optional arguments are denoted by the '--' in their name, e.g.  `--modtran_path`, `--pressure_elevation`. It is important to note that the default radiative transfer engine (RTE) is currently set to sRTMnet, set via `--emulator_path`.\n",
+    "\n",
+    "\n",
+    "#### `INPUT_RADIANCE`\n",
+    "The data is at-sensor radiance in units of $\\mu W \\, cm^{-2} \\, nm^{-1} \\, sr^{-1} $. You may leverage **[isofit.core.units](https://isofit.github.io/isofit/latest/api/isofit/core/units/#isofit.core.units)** module which offers many common conversions. The .hdr file should be used to store the wavelength and fwhm. \n",
+    "\n",
+    "\n",
+    "#### `INPUT_LOC`\n",
+    "\n",
+    "1. **Longitude [degrees]**\n",
+    "    - Range is -180 to 180\n",
+    "\n",
+    "2. **Latitude [degrees]**\n",
+    "    - Range is -90 to 90\n",
+    "\n",
+    "3. **Elevation [meters]**\n",
+    "    - Above mean sea level \n",
+    "\n",
+    "\n",
+    "\n",
+    "#### `INPUT_OBS`\n",
+    "\n",
+    "Note: the names of the keys do not need to match exactly, only the order matters.\n",
+    "\n",
+    "1. **Path length [meters]**\n",
+    "    - Defined as the slant path from the sensor to the surface\n",
+    "\n",
+    "2. **To-sensor azimuth, $\\phi_v$ [degrees]**\n",
+    "    - Ranges from 0-360, measured clockwise from north\n",
+    "\n",
+    "3. **To-sensor zenith, $\\theta_v$ [degrees]**\n",
+    "    - Ranges from 0-90, measured from zenith\n",
+    "\n",
+    "4. **To-sun azimuth, $\\phi_s$ [degrees]**\n",
+    "    - Ranges from 0-360, measured clockwise from north\n",
+    "\n",
+    "5. **To-sun zenith, $\\theta_s$ [degrees]**\n",
+    "    - Ranges from 0-90, measured from zenith\n",
+    "\n",
+    "6. **Phase angle, $\\xi$ [degrees]**\n",
+    "    - $cos(\\xi) = cos(\\theta_s) \\, cos(\\theta_v) \\, + \\, sin(\\theta_s) \\, sin(\\theta_v) \\, cos(\\phi_s - \\phi_v)$\n",
+    "    - $\\xi = arccos(cos(\\xi))$\n",
+    "\n",
+    "7. **Slope, $S$ [degrees]**\n",
+    "    - Ranges from 0-90\n",
+    "\n",
+    "8. **Aspect, $A$ [degrees]**\n",
+    "    - Ranges from 0-360, measured clockwise from north\n",
+    "\n",
+    "9. **Cosine of the local solar illumination angle, $cos(i)$ [unitless]**\n",
+    "    - $cos(i) = cos(\\theta_s) \\, cos(S) \\, + \\, sin(\\theta_s) \\, sin(S) \\, cos(\\phi_s - A) $\n",
+    "\n",
+    "10. **UTC time [decimal]**\n",
+    "    - Ranges from 0 - 24\n",
+    "\n",
+    "11. **Earth-sun distance [AU]**\n",
+    "    - Astronomical Unit as a function of day of year"
    ]
   },
   {