def from_file(cls,
file_name,
beam_index: int = 0,
include_corrections: bool = True
):
""" Instantiates a :class:`~nenupy.astro.pointing.Pointing` object from
a NenuFAR pointing file.
Several beam pointings (analog and/or numerical) could be described
in ``file_name``. The argument ``beam_index`` allows for the selection
of one of them.
:param file_name:
NenuFAR pointing file, either analog (ending with ``.altazA``) or
numerical (ending with ``.altazB``).
:type file_name:
`str`
:param beam_index:
Beam number to take into account.
:type beam_index:
`int`
:param include_corrections:
Include or not the pointing corrections (default is ``True``).
Only has an effect on analog beam corrections.
:type include_corrections:
`bool`
:return:
Pointing derived from a NenuFAR pointing file.
:rtype:
:class:`~nenupy.astro.pointing.Pointing`
:Example:
>>> from nenupy.astro.pointing import Pointing
>>> pointing = Pointing.from_file(
file_name=".../20211104_170000_20211104_200000_JUPITER_TRACKING.altazA",
beam_index=1
)
"""
if file_name.endswith('.altazA'):
try:
pointing = np.loadtxt(
file_name,
skiprows=3,
comments=";",
dtype={
'names': ('time', 'anabeam', 'az', 'el', 'az_cor', 'el_cor', 'freq', 'el_eff'),
'formats': ('U20', 'i4', 'f4', 'f4', 'f4', 'f4', 'U5', 'f4')
}
)
available_beams = pointing["anabeam"]
pointing = pointing[available_beams == beam_index]
azimuths = pointing["az_cor"] if include_corrections else pointing["az"]
elevations = pointing["el_eff"] if include_corrections else pointing["el"]
except ValueError:
# No correction
pointing = np.loadtxt(
file_name,
skiprows=3,
comments=";",
dtype={
'names': ('time', 'anabeam', 'az', 'el', 'freq', 'el_eff'),
'formats': ('U20', 'i4', 'f4', 'f4', 'U5', 'f4')
}
)
available_beams = pointing["anabeam"]
pointing = pointing[available_beams == beam_index]
azimuths = pointing["az"]
elevations = pointing["el_eff"] if include_corrections else pointing["el"]
except IndexError:
# No beamsquint
pointing = np.loadtxt(
file_name,
skiprows=3,
comments=";",
dtype={
'names': ('time', 'anabeam', 'az', 'el', 'az_cor', 'el_cor'),
'formats': ('U20', 'i4', 'f4', 'f4', 'f4', 'f4')
}
)
available_beams = pointing["anabeam"]
pointing = pointing[available_beams == beam_index]
azimuths = pointing["az_cor"] if include_corrections else pointing["az"]
elevations = pointing["el_cor"] if include_corrections else pointing["el"]
if pointing.size == 0:
raise ValueError(
f"Empty pointing, check the beam_index={beam_index} value "
f"(avalaible beam indices: {np.unique(available_beams)})."
)
times = Time(pointing["time"])
azimuths *= u.deg
elevations *= u.deg
if times.size == 1:
# for a transit with multiple ABeams
azimuths = np.append(azimuths, [0]*u.deg)
elevations = np.append(elevations, [90]*u.deg)
times = times.insert(1, times[-1] + TimeDelta(1, format="sec"))
duration = times[1:] - times[:-1]
times = times[:-1]
altaz_coords = SkyCoord(
azimuths[:-1],
elevations[:-1],
frame=AltAz(
obstime=times,
location=nenufar_position
)
)
elif file_name.endswith('.altazB'):
pointing = np.loadtxt(
file_name,
skiprows=2,
comments=";",
dtype={
'names': ('time', 'anabeam', 'digibeam', 'az', 'el', 'l', 'm', 'n'),
'formats': ('U20', 'i4', 'i4', 'f4', 'f4', 'f4', 'f4', 'f4')
}
)
available_beams = pointing["digibeam"]
pointing = pointing[available_beams == beam_index]
if pointing.size == 0:
raise ValueError(
f"Empty pointing, check the beam_index={beam_index} value "
f"(avalaible beam indices: {np.unique(available_beams)})."
)
times = Time(pointing["time"])
duration = times[1:] - times[:-1]
# Add the last duration at the end (supposed to be 10 seconds)
duration = duration.insert(-1, TimeDelta(10, format="sec", scale=duration.scale))
altaz_coords = SkyCoord(
pointing['az'],
pointing["el"],
unit="deg",
frame=AltAz(
obstime=times,
location=nenufar_position
)
)
pointing = cls(
coordinates=altaz_to_radec(altaz=altaz_coords),
time=times,
duration=duration,
observer=nenufar_position
)
pointing.custom_ho_coordinates = altaz_coords
return pointing
