"""
Coordinates.
"""
from astropy.coordinates import (
AltAz,
FunctionTransformWithFiniteDifference,
CIRS,
frame_transform_graph,
)
import warnings
from .telescope_frame import TelescopeFrame
from .nominal_frame import NominalFrame
from .ground_frames import GroundFrame, TiltedGroundFrame, project_to_ground
from .camera_frame import CameraFrame, EngineeringCameraFrame
__all__ = [
"TelescopeFrame",
"CameraFrame",
"EngineeringCameraFrame",
"NominalFrame",
"GroundFrame",
"TiltedGroundFrame",
"project_to_ground",
"MissingFrameAttributeWarning",
]
[docs]class MissingFrameAttributeWarning(Warning):
pass
# astropy requires all AltAz to have locations
# and obstimes so they can be converted into true skycoords
# Also it is required to transform one AltAz into another one
# This forbids it to use AltAz without setting location and obstime
# here, the astropy behaviour is defined so that it is assumed,
# that if no information about location or obstime is known, both are the same
@frame_transform_graph.transform(FunctionTransformWithFiniteDifference, AltAz, AltAz)
def altaz_to_altaz(from_coo, to_frame):
# check if coordinates have obstimes defined
obstime = from_coo.obstime
if from_coo.obstime is None:
warnings.warn(
"AltAz coordinate has no obstime, assuming same frame",
MissingFrameAttributeWarning,
)
obstime = to_frame.obstime
location = from_coo.location
if from_coo.obstime is None:
warnings.warn(
"Horizontal coordinate has no location, assuming same frame",
MissingFrameAttributeWarning,
)
location = to_frame.location
if obstime is None or location is None:
return to_frame.realize_frame(from_coo.spherical)
return from_coo.transform_to(CIRS(obstime=obstime)).transform_to(to_frame)