diff --git a/METIS/METIS.yaml b/METIS/METIS.yaml
index 90ede94..bb58beb 100644
--- a/METIS/METIS.yaml
+++ b/METIS/METIS.yaml
@@ -56,6 +56,13 @@ effects:
       transmission: "!OBS.pupil_transmission"
       minimum_throughput: !!float 0.
 
+  - name : common_fits_keywords
+    decription : FITS keywords common to all modes
+    class : ExtraFitsKeywords
+    include : True
+    kwargs :
+      filename: headers/FITS_common_keywords.yaml
+
 #  - name : metis_adc_residuals
 #    class : AtmosphericDispersionCorrection
 #    include : False
diff --git a/METIS/default.yaml b/METIS/default.yaml
index 835bcff..a3a6a6a 100644
--- a/METIS/default.yaml
+++ b/METIS/default.yaml
@@ -40,6 +40,22 @@ properties:
   auto_exposure:
     fill_frac: 0.75   # fraction to which full well is filled in one DIT
 
+  # Default DPR keywords and template name.
+  # TODO: Perhaps create different 'modes' for each template, with a
+  #       corresponding yaml file with the keywords.
+  tplname: "METIS_img_lm_obs_GenericOffset"
+  catg: "SCIENCE"
+  tech: "IMAGE,LM"
+  type: "OBJECT"
+  # More default properties for the observation
+  mjdobs: "2027-05-04T02:30:00"
+  tplstart: "2027-05-04T02:30:00"
+  tplno: 0
+  tplexpno: 0
+  obsname: "MyScienceTest"
+  ra: 0.0
+  dec: 0.0
+
 mode_yamls:
   - object: observation
     alias: OBS
diff --git a/METIS/docs/example_notebooks/RawHeaders.ipynb b/METIS/docs/example_notebooks/RawHeaders.ipynb
new file mode 100644
index 0000000..12b1805
--- /dev/null
+++ b/METIS/docs/example_notebooks/RawHeaders.ipynb
@@ -0,0 +1,513 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "5cbaae4c-e4ac-423a-93c3-80f67b85566c",
+   "metadata": {},
+   "source": [
+    "# Raw Headers\n",
+    "\n",
+    "A notebook to show the raw headers of the simulated data."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "d3d7858c-b000-436f-91ba-142f04196deb",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import os\n",
+    "import numpy as np\n",
+    "from astropy.io import fits\n",
+    "from astropy import units as u\n",
+    "from astropy.wcs import WCS"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "0f8e6494-3a5f-4469-ba9f-3722791d71ee",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from matplotlib import pyplot as plt\n",
+    "from matplotlib.colors import LogNorm\n",
+    "%matplotlib inline"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "bc15265c-73eb-4752-abb8-cb888c7cf66e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import scopesim as sim\n",
+    "import scopesim_templates\n",
+    "# Edit this path to use where you have downloaded the IRDB packages (see other notebooks).\n",
+    "sim.rc.__config__[\"!SIM.file.local_packages_path\"] = \"../../../\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "45c9a641-3db7-4387-a173-591930519161",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# sim.bug_report()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c4dc4316-fef2-4906-ba0c-8f0bb3b07698",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "e39b7043-dce3-4dbd-8190-5454a20a7910",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['A0V']\n"
+     ]
+    }
+   ],
+   "source": [
+    "star = scopesim_templates.stellar.star(filter_name=\"V\", amplitude=22)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7c44f895-374b-486c-aabe-cdfada73e460",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "id": "e003ed89-244f-4c9b-9424-ad5a32404a1a",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Pixel scale: 0.00547 arcsec / pix\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Plate scale: 0.30389 arcsec / mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS sky corners: [[-0.00155591 -0.00155591]\n",
+      " [-0.00155591  0.00155591]\n",
+      " [ 0.00155591  0.00155591]\n",
+      " [ 0.00155591 -0.00155591]] deg\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS det corners: [[-18.43193261 -18.43193261]\n",
+      " [-18.43193261  18.43193261]\n",
+      " [ 18.43193261  18.43193261]\n",
+      " [ 18.43193261 -18.43193261]] mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane:det WCS Keywords\n",
+      "\n",
+      "Number of WCS axes: 2\n",
+      "CTYPE : 'LINEAR'  'LINEAR'  \n",
+      "CRVAL : 0.0  0.0  \n",
+      "CRPIX : 1024.5  1024.5  \n",
+      "PC1_1 PC1_2  : 1.0  0.0  \n",
+      "PC2_1 PC2_2  : 0.0  1.0  \n",
+      "CDELT : 0.018  0.018  \n",
+      "NAXIS : 2048  2048\n",
+      "DEBUG:astar.scopesim.optics.image_plane:sky None\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Pixel scale: 0.00547 arcsec / pix\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Plate scale: 0.30389 arcsec / mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS sky corners: [[-0.00155591 -0.00155591]\n",
+      " [-0.00155591  0.00155591]\n",
+      " [ 0.00155591  0.00155591]\n",
+      " [ 0.00155591 -0.00155591]] deg\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS det corners: [[-18.43193261 -18.43193261]\n",
+      " [-18.43193261  18.43193261]\n",
+      " [ 18.43193261  18.43193261]\n",
+      " [ 18.43193261 -18.43193261]] mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane:det WCS Keywords\n",
+      "\n",
+      "Number of WCS axes: 2\n",
+      "CTYPE : 'LINEAR'  'LINEAR'  \n",
+      "CRVAL : 0.0  0.0  \n",
+      "CRPIX : 1024.5  1024.5  \n",
+      "PC1_1 PC1_2  : 1.0  0.0  \n",
+      "PC2_1 PC2_2  : 0.0  1.0  \n",
+      "CDELT : 0.018  0.018  \n",
+      "NAXIS : 2048  2048\n",
+      "DEBUG:astar.scopesim.optics.image_plane:sky None\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [ELT]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_EntrWin]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_KM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_KM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_KM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_KM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_KM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_KM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_KM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_KM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_KM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_Dichroic]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_FM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_FM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_FM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM4]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM4]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM4]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM5]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM5]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM5]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [CFO_CM6]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [CFO_CM6]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [CFO_CM6]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [const_90]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [cold_stop]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_M1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_M1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_M1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_M2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_M2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_M2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_M3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_M3]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_M3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_dichroic]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_dichroic]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_LM_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_LM_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_LM_FM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_LM_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_LM_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_LM_FM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_LM_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_LM_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_LM_CM1]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_LM_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_LM_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_LM_CM2]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [IMG_LM_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [IMG_LM_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:transmission not found in either '.meta' or '.table': [IMG_LM_CM3]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [Lp]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [Lp]\n",
+      "DEBUG:astar.scopesim.optics.surface:reflection not found in either '.meta' or '.table': [Lp]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [open]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [open]\n",
+      "DEBUG:astar.scopesim.optics.surface:reflection not found in either '.meta' or '.table': [open]\n",
+      "DEBUG:astar.scopesim.optics.surface:emission not found in either '.meta' or '.table': [quantum_efficiency]\n",
+      "DEBUG:astar.scopesim.optics.surface:emissivity not found in either '.meta' or '.table': [quantum_efficiency]\n",
+      "DEBUG:astar.scopesim.optics.surface:reflection not found in either '.meta' or '.table': [quantum_efficiency]\n",
+      " FOVs:   0%|                                                                                                          | 0/1 [00:00<?, ?it/s]\n",
+      " FOV effects:   0%|                                                                                                   | 0/1 [00:00<?, ?it/s]\u001b[A\n",
+      " FOV effects: 100%|███████████████████████████████████████████████████████████████████████████████████████████| 1/1 [00:00<00:00,  1.21it/s]\u001b[A\n",
+      "                                                                                                                                            \u001b[ADEBUG:astar.scopesim.optics.image_plane_utils:zoom [0.99999634 0.99999634]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:new crpix [1024.5 1024.5]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:sky [[0. 0.]]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:pix [[1023.5 1023.5]]\n",
+      " FOVs: 100%|██████████████████████████████████████████████████████████████████████████████████████████████████| 1/1 [00:01<00:00,  1.09s/it]\n",
+      " Image Plane effects: 0it [00:00, ?it/s]\n"
+     ]
+    },
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Requested exposure time: 1.000 s\n",
+      "Exposure parameters:\n",
+      "                DIT: 0.250 s  NDIT: 4\n",
+      "Total exposure time: 1.000 s\n",
+      "astar.scopesim.detector.detector_array - INFO: Extracting from 1 detectors...\n"
+     ]
+    },
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "INFO:astar.scopesim.detector.detector_array:Extracting from 1 detectors...\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Pixel scale: 0.00547 arcsec / pix\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Plate scale: 0.30389 arcsec / mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS det corners: [[-18.432 -18.432]\n",
+      " [-18.432  18.432]\n",
+      " [ 18.432  18.432]\n",
+      " [ 18.432 -18.432]] mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS sky corners: [[-5.60130048 -5.60130048]\n",
+      " [-5.60130048  5.60130048]\n",
+      " [ 5.60130048  5.60130048]\n",
+      " [ 5.60130048 -5.60130048]] arcsec\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:zoom [1. 1.]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:sky [[0. 0.]]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:pix [[1023.5 1023.5]]\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Pixel scale: 0.00547 arcsec / pix\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:Plate scale: 0.30389 arcsec / mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS det corners: [[-18.432 -18.432]\n",
+      " [-18.432  18.432]\n",
+      " [ 18.432  18.432]\n",
+      " [ 18.432 -18.432]] mm\n",
+      "DEBUG:astar.scopesim.optics.image_plane_utils:WCS sky corners: [[-5.60130048 -5.60130048]\n",
+      " [-5.60130048  5.60130048]\n",
+      " [ 5.60130048  5.60130048]\n",
+      " [ 5.60130048 -5.60130048]] arcsec\n"
+     ]
+    },
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Requested exposure time: 1.000 s\n",
+      "Exposure parameters:\n",
+      "                DIT: 0.250 s  NDIT: 4\n",
+      "Total exposure time: 1.000 s\n"
+     ]
+    }
+   ],
+   "source": [
+    "cmd_img_lm = sim.UserCommands(use_instrument=\"METIS\", set_modes=[\"img_lm\"])\n",
+    "metis_img_lm = sim.OpticalTrain(cmd_img_lm)\n",
+    "metis_img_lm.observe(star)\n",
+    "hdus_img_lm = metis_img_lm.readout()[0]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ea5fff12-568e-46ee-b710-e581d3b7558b",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "824170f2-e16f-46de-b389-7db36efba431",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "header_primary_img_lm = hdus_img_lm[0].header"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "f53fbddb-927f-4ff1-b44e-1265faf8ac6e",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "SIMPLE  =                    T / conforms to FITS standard                      \n",
+      "BITPIX  =                    8 / array data type                                \n",
+      "NAXIS   =                    0 / number of array dimensions                     \n",
+      "EXTEND  =                    T                                                  \n",
+      "MJD-OBS = '2027-05-04T02:30:00'                                                 \n",
+      "RA      =                  0.0                                                  \n",
+      "DEC     =                  0.0                                                  \n",
+      "ORIGIN  = 'SCOPESIM'                                                            \n",
+      "TELESCOP= 'ELT     '                                                            \n",
+      "INSTRUME= 'METIS   '                                                            \n",
+      "AIRMASS =                  1.2                                                  \n",
+      "HIERARCH ESO DPR CATG = 'SCIENCE '                                              \n",
+      "HIERARCH ESO DPR TYPE = 'OBJECT  '                                              \n",
+      "HIERARCH ESO DPR TECH = 'IMAGE,LM'                                              \n",
+      "HIERARCH ESO OBS ID = 42                                                        \n",
+      "HIERARCH ESO OBS NAME = 'TODO    '                                              \n",
+      "HIERARCH ESO OBS START = 'TODO    '                                             \n",
+      "HIERARCH ESO OBS TPLNO = 1                                                      \n",
+      "HIERARCH ESO TPL ID = 'METIS_img_lm_obs_GenericOffset'                          \n",
+      "HIERARCH ESO TPL NAME = 'METIS_img_lm_obs_GenericOffset'                        \n",
+      "HIERARCH ESO TPL EXPNO = 0                                                      \n",
+      "HIERARCH ESO TPL START = '2027-05-04T02:30:00'                                  \n",
+      "HIERARCH ESO DET DIT = 0.25                                                     \n",
+      "HIERARCH ESO DET NDIT = 4                                                       \n",
+      "HIERARCH ESO DET NCORRS NAME = 'TODO    '                                       \n",
+      "HIERARCH ESO DET CUBE MODE = 'F       '                                         \n",
+      "HIERARCH ESO INS DROT POSANG = 0                                                \n",
+      "HIERARCH ESO DRS FILTER = 'Lp      '                                            \n",
+      "HIERARCH ESO DRS NDFILTER = 'open    '                                          \n",
+      "HIERARCH WISE ATMO LOCATION = 'Armazones'                                       \n",
+      "HIERARCH WISE ATMO ALTITUDE = 3060                                              \n",
+      "HIERARCH WISE ATMO LONGITUD = -70.1918                                          \n",
+      "HIERARCH WISE ATMO LATITUDE = -24.5899                                          \n",
+      "HIERARCH WISE ATMO TEMPERAT = 7                                                 \n",
+      "HIERARCH WISE ATMO HUMIDITY = 0.1                                               \n",
+      "HIERARCH WISE ATMO PRESSURE = 0.755                                             \n",
+      "HIERARCH WISE ATMO PWV = 2.5                                                    \n",
+      "HIERARCH WISE DET IMAGE_PL = 0                                                  \n",
+      "HIERARCH WISE DET TEMPERAT = -230                                               \n",
+      "HIERARCH WISE DET DAR VALUE = 0.05                                              \n",
+      "HIERARCH WISE DET SHO STATE = T                                                 \n",
+      "HIERARCH WISE DET QEC FILENAME = 'QE_detector_H2RG_METIS.dat'                   \n",
+      "HIERARCH WISE DET LIN FILENAME = '!DET.linearity.file_name'                     \n",
+      "HIERARCH WISE TEL NAME = 'ELT     '                                             \n",
+      "HIERARCH WISE TEL TELESCOP = 'ELT     '                                         \n",
+      "HIERARCH WISE TEL TER FILENAME = 'TER_ELT_6_mirror_field_track.dat'             \n",
+      "HIERARCH WISE TEL REF FILENAME = 'LIST_ELT_combined.tbl'                        \n",
+      "HIERARCH WISE OCS PXSCALE = 0.00547                                             \n",
+      "HIERARCH WISE OBS TPLNO = 0                                                     \n",
+      "HIERARCH WISE OBS INSTRUME = 'METIS   '                                         \n",
+      "HIERARCH WISE OBS NAME = 'MyScienceTest'                                        \n",
+      "HIERARCH WISE OBS RA = 0.0                                                      \n",
+      "HIERARCH WISE OBS DEC = 0.0                                                     \n"
+     ]
+    }
+   ],
+   "source": [
+    "print(repr(header_primary_img_lm))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fcf146b7-5a68-4e38-a3f4-8c8aa0a46c67",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "1f5b3afd-7f43-4e3b-b6cb-fdc4be5a2f85",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "header_data_img_lm = hdus_img_lm[1].header"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "id": "80a9bf38-4387-40e9-8cc3-8345170e21cf",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "XTENSION= 'IMAGE   '           / Image extension                                \n",
+      "BITPIX  =                  -64 / array data type                                \n",
+      "NAXIS   =                    2                                                  \n",
+      "NAXIS1  =                 2048                                                  \n",
+      "NAXIS2  =                 2048                                                  \n",
+      "PCOUNT  =                    0 / number of parameters                           \n",
+      "GCOUNT  =                    1 / number of groups                               \n",
+      "WCSAXESD=                    2                                                  \n",
+      "CRPIX1D =              1024.5                                                   \n",
+      "CRPIX2D =              1024.5                                                   \n",
+      "CDELT1D =               0.018                                                   \n",
+      "CDELT2D =               0.018                                                   \n",
+      "CUNIT1D = 'mm      '                                                            \n",
+      "CUNIT2D = 'mm      '                                                            \n",
+      "CTYPE1D = 'LINEAR  '                                                            \n",
+      "CTYPE2D = 'LINEAR  '                                                            \n",
+      "CRVAL1D =                 0.0                                                   \n",
+      "CRVAL2D =                 0.0                                                   \n",
+      "LATPOLED=                90.0                                                   \n",
+      "MJDREF  =                 0.0  / [d] MJD of fiducial time                       \n",
+      "ID      = '1       '                                                            \n",
+      "X_CEN   =                  0.0                                                  \n",
+      "Y_CEN   =                  0.0                                                  \n",
+      "X_SIZE  = '2048    '                                                            \n",
+      "Y_SIZE  = '2048    '                                                            \n",
+      "HIERARCH pixel_size = 0.018                                                     \n",
+      "ANGLE   =                  0.0                                                  \n",
+      "GAIN    =                  1.0                                                  \n",
+      "WCSAXES =                    2 / Number of coordinate axes                      \n",
+      "CRPIX1  =               1024.5 / Pixel coordinate of reference point            \n",
+      "CRPIX2  =               1024.5 / Pixel coordinate of reference point            \n",
+      "CDELT1  =              0.00547 / [arcsec] Coordinate increment at reference poin\n",
+      "CDELT2  =              0.00547 / [arcsec] Coordinate increment at reference poin\n",
+      "CUNIT1  = 'arcsec'             / Units of coordinate increment and value        \n",
+      "CUNIT2  = 'arcsec'             / Units of coordinate increment and value        \n",
+      "CTYPE1  = 'LINEAR'             / Coordinate type code                           \n",
+      "CTYPE2  = 'LINEAR'             / Coordinate type code                           \n",
+      "CRVAL1  =                  0.0 / [arcsec] Coordinate value at reference point   \n",
+      "CRVAL2  =                  0.0 / [arcsec] Coordinate value at reference point   \n",
+      "LATPOLE =                 90.0 / [deg] Native latitude of celestial pole        \n",
+      "INHERIT = 'T       '                                                            \n",
+      "EXTNAME = 'DET1.DATA'                                                           \n"
+     ]
+    }
+   ],
+   "source": [
+    "print(repr(header_data_img_lm))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b30ee239-a0c9-4268-b22a-bbdd4bb38c19",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "131ace17-a84c-4a86-87a9-1ce0388a52a5",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c79e4013-ad8b-40b6-b246-c564b9ed6500",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "090e8621-2edc-436b-94ce-4256f3818245",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.11.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/METIS/headers/FITS_common_keywords.yaml b/METIS/headers/FITS_common_keywords.yaml
new file mode 100644
index 0000000..5a5ed8f
--- /dev/null
+++ b/METIS/headers/FITS_common_keywords.yaml
@@ -0,0 +1,163 @@
+- ext_type: PrimaryHDU
+  keywords:
+    # Top level keywords. Several of the top level keywords are described in
+    # ESO-044156, Data Interface Control Document, or DICD (v7).
+    # TODO: Add more keywords from ESO-044156.
+    MJD-OBS: "!OBS.mjdobs"
+    RA: "!OBS.ra"
+    DEC: "!OBS.dec"
+    ORIGIN: "SCOPESIM"
+    TELESCOP: "ELT"
+    INSTRUME: "METIS"
+    AIRMASS: "!OBS.airmass"
+
+    HIERARCH:
+      ESO:
+        # Keywords in the ESO hierarchy. We expect all of these to also appear
+        # in the raw data from the telescope. However, this list is not
+        # exhaustive; the real data will have more keywords.
+        #
+        # ESO-044156, Data Interface Control Document, or DICD (v7), describes
+        # the structure of these header keywords and provides many standardized
+        # keywords. In particular, ESO-044156 defines the default categories,
+        # and also the recommendation to limit the names to 8 characters.
+        DPR:
+          # DPR keywords as defined in the DRLD.
+          #
+          # Currently, the DPR keywords have to be specified as input
+          # parameters. Perhaps we could create a yaml file for each raw
+          # data type.
+          CATG: "!OBS.catg"
+          TYPE: "!OBS.type"
+          TECH: "!OBS.tech"
+        OBS:
+          # Keywords in the Observation category.
+          #
+          # Taken from ESO-044156 (DICD), but they should also be described
+          # elsewhere. Only those somewhat relevant to PIP are included
+          #
+          # TODO: Ensure ScopeSim can simulate Observing Blocks.
+          # TODO: Add more OBS keywords.
+          # TODO: Ensure the OBS keywords are in E-LIS-KUL-MET-1002.
+
+          # A unique numeric id which was assigned to the observation
+          # block by the Observation Handling Subsystem.
+          ID: 42
+
+          # The name of the observation block itself.
+          NAME: "TODO"
+
+          # The exact start time of the OB in the restricted ISO 8601 format.
+          START: "TODO"
+
+          # The template sequence number within the observation block. The
+          #  first template in the observation block shall have the OBS.TPLNO
+          # value of 1.
+          TPLNO: 1
+
+        TPL:
+          # Standard template keywords, however, these are not all included
+          # in the template manual.
+          # TODO: Expand with more standard template keywords.
+          ID:  "!OBS.tplname"
+          NAME: "!OBS.tplname"
+          EXPNO: "!OBS.tplexpno"
+          START: "!OBS.tplstart"
+
+        DET:
+          # Keywords from the detector subsystem.
+          #
+          # E-LIS-KUL-MET-1002 currently only specifies DETi.DIT and DETi.NDIT,
+          # where n=1,2,3. However, our raw files only have data from a single
+          # subinstrument, so we should ensure that DET.DIT and DET.NDIT are
+          # also provided. Idem for DETi.NCORRS.NAME and DET.CUBE.MODE
+          #
+          # NCORRS.NAME and CUBE.MODE from Template Manual.
+          DIT: "!OBS.dit"
+          NDIT: "!OBS.ndit"
+          NCORRS:
+            # Readout mode.
+            # TODO: Put something sensible in DET.NCORRS.NAME
+            NAME: "TODO"
+          CUBE:
+            # TODO: Allow cube mode in ScopeSim.
+            MODE: "F"
+        INS:
+          # Keywords from the instrument subsystem.
+          #
+          # Many more are defined in E-LIS-KUL-MET-1002. Not all possible INS
+          # keywords are applicable to all observation modes.
+          #
+          # TODO: Add the OPTI keywords, but probably in separate yaml files
+          #       for each mode.
+          #OPTI6:
+          #  NAME: "open"
+          DROT:
+            # Derotator position angle.
+            POSANG: 0
+        DRS:
+          # Data Reduction Subsystem keywords as defined in the DRLD.
+          # TODO: Add SLIT / IFU / MASK / PUPIL, but those are perhaps not
+          #       applicable to all observations and thus need their own
+          #       keywords yaml file.
+          FILTER: "!OBS.filter_name"
+          NDFILTER: "!OBS.nd_filter_name"
+
+      WISE:
+        # Extra keywords to fill the (hypothetical) MetisWISE database.
+        # These keywords will not be part of the raw data from the telescope,
+        # and are primarily used for reproducibility.
+        # However, several of these keywords would also be useful for the real
+        # data, and we should consider moving those to the ESO hierarchy
+        # (perhaps in a different category though).
+        ATMO:
+          # Keywords describing the atmosphere
+          LOCATION: "!ATMO.location"
+          ALTITUDE: "!ATMO.altitude"
+          LONGITUD: "!ATMO.longitude"
+          LATITUDE: "!ATMO.latitude"
+          TEMPERAT: "!ATMO.temperature"
+          HUMIDITY: "!ATMO.humidity"
+          PRESSURE: "!ATMO.pressure"
+          PWV: "!ATMO.pwv"
+        DET:
+          IMAGE_PL: "!DET.image_plane_id"
+          TEMPERAT: "!DET.temperature"
+          DAR:
+            # TODO: directly ask the dark_current effect for its value, like
+            #VALUE: "#dark_current.value"
+            # However, that currently does not work because that resolves to
+            # !DET.dark_current which is not subsequently resolved.
+            VALUE: "!DET.dark_current"
+          SHO:
+            STATE: "#shot_noise.include"
+          QEC:
+            FILENAME: "#quantum_efficiency.filename"
+          LIN:
+            FILENAME: "#detector_linearity.filename"
+          # TODO: Include a ReferencePixelBorder effect?
+          #REF:
+          #  ALL: "#border_reference_pixels.all"
+        TEL:
+          NAME: "ELT"
+          TELESCOP: "ELT"
+          TER:
+            FILENAME: "!TEL.ter_curve.filename"
+          REF:
+            FILENAME: "#telescope_reflection.filename"
+        OCS:
+          PXSCALE: "!INST.pixel_scale"
+        OBS:
+          TPLNO: "!OBS.tplno"
+          INSTRUME: "METIS"
+          NAME: "!OBS.obsname"
+          RA: "!OBS.ra"
+          DEC: "!OBS.dec"
+
+- ext_type: ImageHDU
+  # Keyword for extension HDUs.
+  keywords:
+    INHERIT: "T"
+    # Will resolve to e.g. DET1.DATA, DET2.DATA etc. This allows us to reorder
+    # the extensions in case they are shuffled.
+    EXTNAME: "DET§.DATA"