"""
Spectrograph utility methods.
"""
from IPython import embed
import os.path
import numpy as np
from astropy.io import fits
from pypeit import spectrographs
from pypeit import msgs
[docs]def load_spectrograph(spec):
"""
Instantiate a spectrograph from the available subclasses of
:class:`~pypeit.spectrographs.spectrograph.Spectrograph`.
Args:
spec (:obj:`str`, :class:`~pypeit.spectrographs.spectrograph.Spectrograph`):
The spectrograph to instantiate. If the input object is ``None``
or has :class:`~pypeit.spectrographs.spectrograph.Spectrograph`
as a base class, the instance is simply returned. If it is a
string, the string is used to instantiate the relevant
spectrograph instance.
Returns:
:class:`~pypeit.spectrographs.spectrograph.Spectrograph`: The
spectrograph used to obtain the data to be reduced.
Raises:
PypeItError:
Raised if the input is a string that does not select a recognized
PypeIt spectrograph.
"""
if spec is None or isinstance(spec, spectrographs.spectrograph.Spectrograph):
return spec
classes = spectrographs.spectrograph_classes()
if spec in classes.keys():
return classes[spec]()
# Check if we were given a file, and if so try to read the spectrograph type from its header
if os.path.isfile(spec):
header = fits.getheader(spec)
if 'PYP_SPEC' in header:
pyp_spec = header['PYP_SPEC']
if pyp_spec in classes.keys():
spectrograph = classes[pyp_spec]()
if 'DISPNAME' in header:
spectrograph.dispname = header['DISPNAME']
return spectrograph
else:
msgs.error(f'Unknown PYP_SPEC {pyp_spec} found in {spec}')
else:
msgs.error(f'{spec} did not contain PYP_SPEC in its header')
msgs.error('{0} is not a supported spectrograph.'.format(spec))