def geometric_delay(baselines, skypos, altaz=False, dircos=False, hadec=True,
units='mks', latitude=None):
"""
---------------------------------------------------------------------
Estimates the geometric delays matrix for different baselines from
different sky positions.
Inputs:
baselines: x, y, and z components of baseline vectors in a Mx3 numpy
array
skypos: Nx2 (Alt-Az or HA-Dec) or Nx3 (direction cosines) numpy array
of sky positions
altaz: [Boolean flag, default=False] If True, skypos is in Alt-Az
coordinates system
hadec: [Boolean flag, default=True] If True, skypos is in HA-Dec
coordinates system
dircos: [Boolean flag, default=False] If True, skypos is in direction
cosines coordinates system
units: Units of baselines. Default='mks'. Alternative is 'cgs'.
latitude: Latitude of the observatory. Required if hadec is True.
Outputs:
geometric delays [NxM numpy array] Geometric delay for every combination
of baselines and skypos.
---------------------------------------------------------------------
"""
try:
baselines, skypos
except NameError:
raise NameError('baselines and/or skypos not defined in geometric_delay().')
if (altaz)+(dircos)+(hadec) != 1:
raise ValueError('One and only one of altaz, dircos, hadec must be set to True.')
if hadec and (latitude is None):
raise ValueError('Latitude must be specified when skypos is in HA-Dec format.')
try:
units
except NameError:
print('No units provided. Assuming MKS units.')
units = 'mks'
if (units != 'mks') and (units != 'cgs'):
print('Units should be specified to be one of MKS or CGS. Default=MKS')
print('Proceeding with MKS units.')
units = 'mks'
if not isinstance(baselines, NP.ndarray):
raise TypeError('baselines should be a Nx3 numpy array in geometric_delay().')
if len(baselines.shape) == 1:
baselines = baselines.reshape(1,-1)
if baselines.shape[1] == 1:
baselines = NP.hstack(baselines, NP.zeros((baselines.size,2)))
elif baselines.shape[1] == 2:
baselines = NP.hstack(baselines, NP.zeros((baselines.size,1)))
elif baselines.shape[1] > 3:
baselines = baselines[:,:3]
if altaz or hadec:
if len(skypos.shape) < 2:
if skypos.size != 2:
raise ValueError('Sky position in altitude-azimuth or HA-Dec should consist of 2 elements.')
else:
skypos = skypos.reshape(1,-1)
elif len(skypos.shape) > 2:
raise ValueError('Sky positions should be a Nx2 numpy array if using altitude-azimuth of HA-Dec.')
else:
if skypos.shape[1] != 2:
raise ValueError('Sky positions should be a Nx2 numpy array if using altitude-azimuth of HA-Dec.')
if altaz:
dc = GEOM.altaz2dircos(skypos, 'degrees')
else:
dc = GEOM.altaz2dircos(GEOM.hadec2altaz(skypos, latitude, 'degrees'), 'degrees')
else:
if len(skypos.shape) < 2:
if skypos.size != 3:
raise ValueError('Sky position in direction cosines should consist of 3 elements.')
else:
skypos = skypos.reshape(1,-1)
elif len(skypos.shape) > 2:
raise ValueError('Sky positions should be a Nx3 numpy array if using direction cosines.')
else:
if skypos.shape[1] != 3:
raise ValueError('Sky positions should be a Nx3 numpy array if using direction cosines.')
dc = skypos
# Set the speed of light in MKS or CGS units
if units == 'mks': c = FCNST.c
elif units == 'cgs': c = FCNST.c * 1e2
# geometric_delays = delay_envelope(baselines, dc, units)[:,:,-1]
geometric_delays = NP.dot(dc, baselines.T)/c
return geometric_delays
def geometric_delay(baselines,
skypos,
altaz=False,
dircos=False,
hadec=True,
units='mks',
latitude=None):
"""
---------------------------------------------------------------------
Estimates the geometric delays matrix for different baselines from
different sky positions.
Inputs:
baselines: x, y, and z components of baseline vectors in a Mx3 numpy
array
skypos: Nx2 (Alt-Az or HA-Dec) or Nx3 (direction cosines) numpy array
of sky positions
altaz: [Boolean flag, default=False] If True, skypos is in Alt-Az
coordinates system
hadec: [Boolean flag, default=True] If True, skypos is in HA-Dec
coordinates system
dircos: [Boolean flag, default=False] If True, skypos is in direction
cosines coordinates system
units: Units of baselines. Default='mks'. Alternative is 'cgs'.
latitude: Latitude of the observatory. Required if hadec is True.
Outputs:
geometric delays [NxM numpy array] Geometric delay for every combination
of baselines and skypos.
---------------------------------------------------------------------
"""
try:
baselines, skypos
except NameError:
raise NameError(
'baselines and/or skypos not defined in geometric_delay().')
if (altaz) + (dircos) + (hadec) != 1:
raise ValueError(
'One and only one of altaz, dircos, hadec must be set to True.')
if hadec and (latitude is None):
raise ValueError(
'Latitude must be specified when skypos is in HA-Dec format.')
try:
units
except NameError:
print 'No units provided. Assuming MKS units.'
units = 'mks'
if (units != 'mks') and (units != 'cgs'):
print 'Units should be specified to be one of MKS or CGS. Default=MKS'
print 'Proceeding with MKS units.'
units = 'mks'
if not isinstance(baselines, NP.ndarray):
raise TypeError(
'baselines should be a Nx3 numpy array in geometric_delay().')
if len(baselines.shape) == 1:
baselines = baselines.reshape(1, -1)
if baselines.shape[1] == 1:
baselines = NP.hstack(baselines, NP.zeros((baselines.size, 2)))
elif baselines.shape[1] == 2:
baselines = NP.hstack(baselines, NP.zeros((baselines.size, 1)))
elif baselines.shape[1] > 3:
baselines = baselines[:, :3]
if altaz or hadec:
if len(skypos.shape) < 2:
if skypos.size != 2:
raise ValueError(
'Sky position in altitude-azimuth or HA-Dec should consist of 2 elements.'
)
else:
skypos = skypos.reshape(1, -1)
elif len(skypos.shape) > 2:
raise ValueError(
'Sky positions should be a Nx2 numpy array if using altitude-azimuth of HA-Dec.'
)
else:
if skypos.shape[1] != 2:
raise ValueError(
'Sky positions should be a Nx2 numpy array if using altitude-azimuth of HA-Dec.'
)
if altaz:
dc = GEOM.altaz2dircos(skypos, 'degrees')
else:
dc = GEOM.altaz2dircos(
GEOM.hadec2altaz(skypos, latitude, 'degrees'), 'degrees')
else:
if len(skypos.shape) < 2:
if skypos.size != 3:
raise ValueError(
'Sky position in direction cosines should consist of 3 elements.'
)
else:
skypos = skypos.reshape(1, -1)
elif len(skypos.shape) > 2:
raise ValueError(
'Sky positions should be a Nx3 numpy array if using direction cosines.'
)
else:
if skypos.shape[1] != 3:
raise ValueError(
'Sky positions should be a Nx3 numpy array if using direction cosines.'
)
dc = skypos
# Set the speed of light in MKS or CGS units
if units == 'mks': c = FCNST.c
elif units == 'cgs': c = FCNST.c * 1e2
# geometric_delays = delay_envelope(baselines, dc, units)[:,:,-1]
geometric_delays = NP.dot(dc, baselines.T) / c
return geometric_delays
def test_altaz2dircos():
altaz = NP.asarray([[90.0, 270.0], [0.0, 90.0]]).reshape(-1,2)
dircos = NP.asarray([[0.0, 0.0, 1.0],[1.0, 0.0, 0.0]]).reshape(-1,3)
expected_dircos = GEOM.altaz2dircos(altaz, units='degrees')
NP.testing.assert_allclose(dircos, expected_dircos, atol=1e-12)
def test_altaz2dircos():
altaz = NP.asarray([[90.0, 270.0], [0.0, 90.0]]).reshape(-1, 2)
dircos = NP.asarray([[0.0, 0.0, 1.0], [1.0, 0.0, 0.0]]).reshape(-1, 3)
expected_dircos = GEOM.altaz2dircos(altaz, units='degrees')
NP.testing.assert_allclose(dircos, expected_dircos, atol=1e-12)
