Allow arbitrary FITS headers

CHANGELOG.rst

@@ -8,10 +8,11 @@ Changelog
 Added
 ~~~~~
 
+* Allow for arbitrary FITS headers. Keywords will be added as `HIERARCH` cards if they don't conform to FITS standard (using ``astropy`` machinery).
 * A "developer" version of the ``panoptes-pocs`` docker image is cloudbuilt automatically on merge with ``develop``. (@wtgee #1010)
 * Better error checking in cameras, including ability to store error. (@AnthonyHorton #1007)
 * Added ``error.InvalidConfig`` exception. (@wtgee #1007)
-* Config options to control camera processing options and allow for `defaults` in the config that applies to all cameras: (@wtgee #1007)
+* Config options to control camera processing options and allow for `defaults` in the config that applies to all cameras: (@wtgee #1007 & #1009)
 
   * ``cameras.defaults.compress_fits`` if FITS files should be fpacked. Default True.
   * ``cameras.defaults.record_observations`` if observation metadata should be recorded. Default True.

src/panoptes/pocs/camera/camera.py

@@ -965,13 +965,23 @@ def _process_fits(self, file_path, metadata):
         self.logger.debug(f"Updating FITS headers: {file_path} with {metadata=}")
         with fits.open(file_path, 'update') as f:
             hdu = f[0]
-            for metadata_key, field_info in fields.items():
-                fits_key = field_info['keyword']
-                fits_comment = field_info.get('comment', '')
-                # Get the value from either the metadata, the default, or use blank string.
-                fits_value = metadata.get(metadata_key, field_info.get('default', ''))
+            for metadata_key, metadata_value in metadata.items():
+                try:
+                    field_info = fields[metadata_key]
+                    # for metadata_key, field_info in fields.items():
+                    fits_key = field_info['keyword']
+                    fits_comment = field_info.get('comment', '')
+                    # Get the value from either the metadata, the default, or use blank string.
+                    fits_value = metadata.get(metadata_key, field_info.get('default', ''))
+
+                    self.logger.trace(f'Setting {fits_key=} = {fits_value=} {fits_comment=}')
+                except KeyError:
+                    self.logger.trace(f'No mapping found for metadata {metadata_key}'
+                                      f', will attempt to add as-is.')
+                    fits_key = metadata_key
+                    fits_comment = ''
+                    fits_value = metadata_value
 
-                self.logger.trace(f'Setting {fits_key=} = {fits_value=} {fits_comment=}')
                 hdu.header.set(fits_key, fits_value, fits_comment)
 
             self.logger.debug(f"Finished FITS headers: {file_path}")

src/panoptes/pocs/tests/test_camera.py

@@ -494,20 +494,38 @@ def test_observation(camera, images_dir):
     assert len(glob.glob(observation_pattern)) == 1
 
 
-def test_observation_headers_and_blocking(camera, images_dir):
+def test_observation_blocking(camera, images_dir):
     """
     Tests functionality of take_observation()
     """
     field = Field('Test Observation', '20h00m43.7135s +22d42m39.0645s')
     observation = Observation(field, exptime=1.5 * u.second)
     observation.seq_time = '19991231T235559'
-    camera.take_observation(observation, headers={'field_name': 'TESTVALUE'}, blocking=True)
+    camera.take_observation(observation, blocking=True)
+    observation_pattern = os.path.join(images_dir, 'TestObservation',
+                                       camera.uid, observation.seq_time, '*.fits*')
+    image_files = glob.glob(observation_pattern)
+    assert len(image_files) == 1
+
+
+def test_observation_headers(camera, images_dir):
+    """
+    Tests functionality of take_observation()
+    """
+    field = Field('Test Observation', '20h00m43.7135s +22d42m39.0645s')
+    observation = Observation(field, exptime=1.5 * u.second)
+    observation.seq_time = '19991231T235559'
+
+    # Test assigned and arbitrary headers.
+    headers = {'field_name': 'TESTVALUE', 'non-conforming-header': 'says-hi'}
+    camera.take_observation(observation, headers=headers, blocking=True)
     observation_pattern = os.path.join(images_dir, 'TestObservation',
                                        camera.uid, observation.seq_time, '*.fits*')
     image_files = glob.glob(observation_pattern)
     assert len(image_files) == 1
     headers = fits_utils.getheader(image_files[0])
     assert fits_utils.getval(image_files[0], 'FIELD') == 'TESTVALUE'
+    assert fits_utils.getval(image_files[0], 'non-conforming-header') == 'says-hi'
 
 
 def test_observation_nofilter(camera, images_dir):