def set_pointing(self, az=0, alt=n.pi/2, twist=0):
"""Set the antenna beam to point at (az, alt) with specified
right-hand twist to polarizations. Polarization y is assumed
to be +pi/2 azimuth from pol x."""
y, z = n.array([0,1,0]), n.array([0,0,1])
# Twist is negative b/c we apply it to the coords, not the beam
rot = coord.rot_m(-twist, z)
rot = n.dot(rot, coord.rot_m(alt-n.pi/2, y))
rot = n.dot(rot, coord.rot_m(-az, z))
self.rot_pol_x = rot
self.rot_pol_y = n.dot(coord.rot_m(-n.pi/2, z), rot)
def set_pointing(self, az=0, alt=np.pi/2, twist=0):
"""Set the antenna beam to point at (az, alt) with specified
right-hand twist to polarizations. Polarization y is assumed
to be +pi/2 azimuth from pol x."""
y, z = np.array([0,1,0]), np.array([0,0,1])
# Twist is negative b/c we apply it to the coords, not the beam
rot = coord.rot_m(-twist, z)
rot = np.dot(rot, coord.rot_m(alt-np.pi/2, y))
# NOTE the az, alt definition, az (clockwise around z = up, 0 at x axis = north), alt (from horizon), see also coord.azalt2top
# rot = np.dot(rot, coord.rot_m(-az, z))
rot = np.dot(rot, coord.rot_m(-(np.pi/2 - az), z))
self.rot_pol_x = rot
self.rot_pol_y = np.dot(coord.rot_m(-np.pi/2, z), rot)
def set_ephemtime(self, t=None):
"""Set current time as derived from the ephem package. Recalculates
matrix for projecting baselines into current positions."""
if t is None: t = ephem.now()
self.date, self.epoch = t, t
self._eq2now = coord.rot_m(-self.sidereal_time(), n.array([0., 0.,
1.]))
def set_ephemtime(self, t=None):
"""Set current time as derived from the ephem package. Recalculates
matrix for projecting baselines into current positions."""
if t is None: t = ephem.now()
self.date, self.epoch = t, t
self._eq2now = coord.rot_m(-self.sidereal_time(), n.array([0.,0.,1.]))
