def annual_parallax(self, time_to_treat):
"""Compute the position shift due to the Earth movement. Please have a look on :
"Resolution of the MACHO-LMC-5 Puzzle: The Jerk-Parallax Microlens Degeneracy"
Gould, Andrew 2004. http://adsabs.harvard.edu/abs/2004ApJ...606..319G
:param time_to_treat: a numpy array containing the time where you want to compute this
effect.
:return: the shift induce by the Earth motion around the Sun
:rtype: array_like
**WARNING** : this is a geocentric point of view.
slalib use MJD time definition, which is MJD = JD-2400000.5
"""
to_par_mjd = self.to_par - 2400000.5
Earth_position_time_reference = slalib.sla_epv(to_par_mjd)
Sun_position_time_reference = -Earth_position_time_reference[0]
Sun_speed_time_reference = -Earth_position_time_reference[1]
delta_Sun = []
for time in time_to_treat:
time_mjd = time - 2400000.5
Earth_position = slalib.sla_epv(time_mjd)
Sun_position = -Earth_position[0]
delta_sun = Sun_position - (time_mjd - to_par_mjd) * Sun_speed_time_reference - Sun_position_time_reference
delta_Sun.append(delta_sun.tolist())
delta_Sun = np.array(delta_Sun)
delta_Sun_projected = np.array(
[np.dot(delta_Sun, self.North), np.dot(delta_Sun, self.East)])
return delta_Sun_projected
def annual_parallax(self, time_to_treat):
"""Compute the position shift due to the Earth movement. Please have a look on :
"Resolution of the MACHO-LMC-5 Puzzle: The Jerk-Parallax Microlens Degeneracy"
Gould, Andrew 2004. http://adsabs.harvard.edu/abs/2004ApJ...606..319G
:param time_to_treat: a numpy array containing the time where you want to compute this
effect.
:return: the shift induce by the Earth motion around the Sun
:rtype: array_like
**WARNING** : this is a geocentric point of view.
slalib use MJD time definition, which is MJD = JD-2400000.5
"""
to_par_mjd = self.to_par - 2400000.5
Earth_position_time_reference = slalib.sla_epv(to_par_mjd)
Sun_position_time_reference = -Earth_position_time_reference[0]
Sun_speed_time_reference = -Earth_position_time_reference[1]
delta_Sun = []
for time in time_to_treat:
time_mjd = time - 2400000.5
Earth_position = slalib.sla_epv(time_mjd)
Sun_position = -Earth_position[0]
delta_sun = Sun_position - (time_mjd - to_par_mjd) * Sun_speed_time_reference - Sun_position_time_reference
delta_Sun.append(delta_sun.tolist())
delta_Sun = np.array(delta_Sun)
delta_Sun_projected = np.array(
[np.dot(delta_Sun, self.North), np.dot(delta_Sun, self.East)])
return delta_Sun_projected
def jd_to_hjd(t, target_position, debug=False):
"""Calculate the HJD timestamp corresponding to the JD given for the
current event.
Inputs:
t is an astropy Time object
target_position is a tuple of (RA, Dec) in decimal degrees
Outputs:
hjd float
"""
if debug == True:
print 'TIME JD: ',t, t.jd
# Calculate the MJD (UTC) timestamp:
mjd_utc = t.jd - 2400000.5
if debug == True:
print 'TIME MJD_UTC: ',mjd_utc
# Correct the MJD to TT:
mjd_tt = mjd_utc2mjd_tt(mjd_utc)
if debug == True:
print 'TIME MJD_TT: ',mjd_tt, t.tt.jd
# Calculate Earth's position and velocity, both heliocentric
# and barycentric for this date
(earth_helio_position, vh, pb, vb) = S.sla_epv( mjd_tt )
if debug == True:
print 'Earth Cartesian position: ',earth_helio_position
print 'Target cartesian position: ', target_position
# Calculate the light travel time delay from the target to
# the Sun:
dv = S.sla_dvdv( earth_helio_position, target_position )
tcorr = dv * ( constants.au.value / constants.c.value )
if debug == True:
print 'TIME tcorr: ', tcorr, 's', (tcorr/60.0),'mins'
# Calculating the HJD:
hjd = mjd_tt + tcorr/86400.0 + 2400000.5
if debug == True:
print 'TIME HJD: ',hjd,'\n'
return hjd
def HJD_to_JD(self, time_to_transform):
"""Transform the input time from HJD to JD.
:param array_like time_to_transform: the numpy array containing the time in HJD you want
to transform in JD.
:return: the time in JD
:rtype: array_like
"""
AU = self.AU
light_speed = self.speed_of_light
time_correction = []
# DTT=[]
for time in time_to_transform:
count = 0
jd = np.copy(time)
while count < 3:
Earth_position = slalib.sla_epv(jd)
Sun_position = -Earth_position[0]
Sun_angles = slalib.sla_dcc2s(Sun_position)
target_angles_in_the_sky = self.target_angles_in_the_sky
Time_correction = np.sqrt(
Sun_position[0] ** 2 + Sun_position[1] ** 2 + Sun_position[
2] ** 2) * AU / light_speed * (
np.sin(Sun_angles[1]) * np.sin(
target_angles_in_the_sky[1]) + np.cos(
Sun_angles[1]) * np.cos(
target_angles_in_the_sky[1]) * np.cos(
target_angles_in_the_sky[0] - Sun_angles[0])) / (
3600 * 24.0)
count = count + 1
# DTT.append(slalib.sla_dtt(jd)/(3600*24))
time_correction.append(Time_correction)
JD = time_to_transform + np.array(time_correction)
return JD
def jd_to_hjd(t, target_position, debug=False):
"""Calculate the HJD timestamp corresponding to the JD given for the
current event.
Inputs:
t is an astropy Time object
target_position is a tuple of (RA, Dec) in decimal degrees
Outputs:
hjd float
"""
if debug == True:
print('TIME JD: ', t, t.jd)
# Calculate the MJD (UTC) timestamp:
mjd_utc = t.jd - 2400000.5
if debug == True:
print('TIME MJD_UTC: ', mjd_utc)
# Correct the MJD to TT:
mjd_tt = mjd_utc2mjd_tt(mjd_utc)
if debug == True:
print('TIME MJD_TT: ', mjd_tt, t.tt.jd)
# Calculate Earth's position and velocity, both heliocentric
# and barycentric for this date
(earth_helio_position, vh, pb, vb) = S.sla_epv(mjd_tt)
if debug == True:
print('Earth Cartesian position: ', earth_helio_position)
print('Target cartesian position: ', target_position)
# Calculate the light travel time delay from the target to
# the Sun:
dv = S.sla_dvdv(earth_helio_position, target_position)
tcorr = dv * (constants.au.value / constants.c.value)
if debug == True:
print('TIME tcorr: ', tcorr, 's', (tcorr / 60.0), 'mins')
# Calculating the HJD:
hjd = mjd_tt + tcorr / 86400.0 + 2400000.5
if debug == True:
print('TIME HJD: ', hjd, '\n')
return hjd
def HJD_to_JD(self, time_to_transform):
"""Transform the input time from HJD to JD.
:param array_like time_to_transform: the numpy array containing the time in HJD you want
to transform in JD.
:return: the time in JD
:rtype: array_like
"""
AU = self.AU
light_speed = self.speed_of_light
time_correction = []
# DTT=[]
for time in time_to_transform:
count = 0
jd = np.copy(time)
while count < 3:
Earth_position = slalib.sla_epv(jd)
Sun_position = -Earth_position[0]
Sun_angles = slalib.sla_dcc2s(Sun_position)
target_angles_in_the_sky = self.target_angles_in_the_sky
Time_correction = np.sqrt(
Sun_position[0] ** 2 + Sun_position[1] ** 2 + Sun_position[
2] ** 2) * AU / light_speed * (
np.sin(Sun_angles[1]) * np.sin(
target_angles_in_the_sky[1]) + np.cos(
Sun_angles[1]) * np.cos(
target_angles_in_the_sky[1]) * np.cos(
target_angles_in_the_sky[0] - Sun_angles[0])) / (
3600 * 24.0)
count = count + 1
# DTT.append(slalib.sla_dtt(jd)/(3600*24))
time_correction.append(Time_correction)
JD = time_to_transform + np.array(time_correction)
return JD
