def create_random_pointings(center,
npointings,
dtheta,
date_obs=None,
period=None,
latitude=None,
longitude=None,
seed=None):
"""
Return pointings randomly and uniformly distributed in a spherical cap.
Parameters
----------
center : 2-tuple
The R.A. and declination of the center of the FOV, in degrees.
npointings : int
The number of requested pointings
dtheta : float
The maximum angular distance to the center.
date_obs : str or astropy.time.Time, optional
The starting date of the observation (UTC).
period : float, optional
The sampling period of the pointings, in seconds.
latitude : float, optional
The observer's latitude [degrees]. Default is DOMEC's.
longitude : float, optional
The observer's longitude [degrees]. Default is DOMEC's.
"""
r = np.random.RandomState(seed)
cosdtheta = np.cos(np.radians(dtheta))
theta = np.degrees(
np.arccos(cosdtheta + (1 - cosdtheta) * r.rand(npointings)))
phi = r.rand(npointings) * 360
pitch = r.rand(npointings) * 360
p = QubicSampling(npointings,
date_obs=date_obs,
period=period,
latitude=latitude,
longitude=longitude)
time = p.date_obs + TimeDelta(p.time, format='sec')
c2s = Cartesian2SphericalOperator('azimuth,elevation', degrees=True)
e2h = CartesianEquatorial2HorizontalOperator('NE', time, p.latitude,
p.longitude)
rot = Rotation3dOperator("ZY'", center[0], 90 - center[1], degrees=True)
s2c = Spherical2CartesianOperator('zenith,azimuth', degrees=True)
rotation = c2s(e2h(rot(s2c)))
coords = rotation(np.asarray([theta.T, phi.T]).T)
p.azimuth = coords[..., 0]
p.elevation = coords[..., 1]
p.pitch = pitch
p.angle_hwp = r.random_integers(0, 7, npointings) * 11.25
p.fix_az = False
return p
def cartesian_galactic2instrument(self):
"""
Return the galactic-to-instrument transform.
"""
time = self.date_obs + TimeDelta(self.time, format='sec')
with rule_manager(none=False):
r = Rotation3dOperator("ZY'Z''", self.azimuth, 90 - self.elevation,
self.pitch, degrees=True).T * \
CartesianEquatorial2HorizontalOperator(
'NE', time, self.latitude, self.longitude) * \
CartesianGalactic2EquatorialOperator()
return r
def create_repeat_pointings(center,
npointings,
dtheta,
nhwp_angles=3,
date_obs=None,
period=None,
latitude=None,
longitude=None,
seed=None):
"""
Return pointings randomly and uniformly distributed in a spherical cap.
The same pointing is repeated nhwp_angles times with a different
hwp angle each time.
Parameters
----------
center : 2-tuple
The R.A. and declination of the center of the FOV, in degrees.
npointings : int
The number of requested pointings
dtheta : float
The maximum angular distance to the center.
nhwp_angles : int
The number of HWP angles used.
date_obs : str or astropy.time.Time, optional
The starting date of the observation (UTC).
period : float, optional
The sampling period of the pointings, in seconds.
latitude : float, optional
The observer's latitude [degrees]. Default is DOMEC's.
longitude : float, optional
The observer's longitude [degrees]. Default is DOMEC's.
seed : int
Random seed.
"""
r = np.random.RandomState(seed)
nrandom = np.int(npointings /
nhwp_angles) # number of real random pointings
# Creation of nrandom pointing
cosdtheta = np.cos(np.radians(dtheta))
theta = np.degrees(np.arccos(cosdtheta +
(1 - cosdtheta) * r.rand(nrandom)))
phi = r.rand(nrandom) * 360
pitch = r.rand(nrandom) * 360
p = QubicSampling(nrandom,
date_obs=date_obs,
period=period,
latitude=latitude,
longitude=longitude)
time = p.date_obs + TimeDelta(p.time, format='sec')
c2s = Cartesian2SphericalOperator('azimuth,elevation', degrees=True)
e2h = CartesianEquatorial2HorizontalOperator('NE', time, p.latitude,
p.longitude)
rot = Rotation3dOperator("ZY'", center[0], 90 - center[1], degrees=True)
s2c = Spherical2CartesianOperator('zenith,azimuth', degrees=True)
rotation = c2s(e2h(rot(s2c)))
coords = rotation(np.asarray([theta.T, phi.T]).T)
p.azimuth = coords[..., 0]
p.elevation = coords[..., 1]
p.pitch = pitch
p.fix_az = False
# Replication of the same pointing with others fix hwp angles
pp = QubicSampling(nrandom * nhwp_angles,
date_obs=date_obs,
period=period,
latitude=latitude,
longitude=longitude)
pp.azimuth = np.tile(p.azimuth, nhwp_angles)
pp.elevation = np.tile(p.elevation, nhwp_angles)
pp.pitch = np.tile(p.pitch, nhwp_angles)
pp.time = np.tile(p.time, nhwp_angles)
pp.angle_hwp = np.zeros(nrandom * nhwp_angles)
pp.fix_az = False
for hwp in range(nhwp_angles):
pp.angle_hwp[hwp * nrandom:(hwp + 1) * nrandom] = np.array(
np.rad2deg(hwp * np.pi / (nhwp_angles * 2)))
return pp
def create_random_pointings(center,
npointings,
dtheta,
hwp_stepsize,
date_obs=None,
period=None,
latitude=None,
longitude=None,
seed=None):
"""
Return pointings randomly and uniformly distributed in a spherical cap.
1) Creates random coordinates theta, phi. Range: 0 < theta < dtheta, 0 < phi < 360
(then are converted from spherical to cartesian coordinates),
2) It rotates the points to center them in direction (RA, DEC) using Rotation3dOperator
(equatorial reference system)
3) Convertion: Equatorial to Horizontal reference system
(using CartesianEquatorial2HorizontalOperator's operator)
4) Back to cartesian coordinates (using Cartesian2SphericalOperator)
Parameters
----------
center : 2-tuple
The R.A. and declination of the center of the FOV, in degrees.
npointings : int
The number of requested pointings
dtheta : float
The maximum angular distance to the center.
hwp_stepsize : float
Step angle size for the HWP.
date_obs : str or astropy.time.Time, optional
The starting date of the observation (UTC).
period : float, optional
The sampling period of the pointings, in seconds.
latitude : float, optional
The observer's latitude [degrees]. Default is DOMEC's.
longitude : float, optional
The observer's longitude [degrees]. Default is DOMEC's.
seed : int
Random seed.
"""
r = np.random.RandomState(seed)
cosdtheta = np.cos(np.radians(dtheta))
theta = np.degrees(
np.arccos(cosdtheta + (1 - cosdtheta) * r.rand(npointings)))
phi = r.rand(npointings) * 360
pitch = r.rand(npointings) * 360
p = QubicSampling(npointings,
date_obs=date_obs,
period=period,
latitude=latitude,
longitude=longitude)
time = p.date_obs + TimeDelta(p.time, format='sec')
c2s = Cartesian2SphericalOperator('azimuth,elevation', degrees=True)
e2h = CartesianEquatorial2HorizontalOperator('NE', time, p.latitude,
p.longitude)
rot = Rotation3dOperator("ZY'", center[0], 90 - center[1], degrees=True)
s2c = Spherical2CartesianOperator('zenith,azimuth', degrees=True)
rotation = c2s(e2h(rot(s2c)))
coords = rotation(np.asarray([theta.T, phi.T]).T)
p.azimuth = coords[..., 0]
p.elevation = coords[..., 1]
p.pitch = pitch
p.fix_az = False
p.angle_hwp = r.randint(0, int(90 / hwp_stepsize + 1),
npointings) * hwp_stepsize
return p