def Period(current,start_time):
start=Time(start_time,format='mjd',scale='utc').mjd
current=start+(float(current)/(60*60*24))
eph1957 = ELL1Ephemeris('psrj1959.par')
jpleph = JPLEphemeris(de405)
mjd = Time(current, format='mjd', scale='utc',
lon=(74*u.deg+02*u.arcmin+59.07*u.arcsec).to(u.deg).value,
lat=(19*u.deg+05*u.arcmin+47.46*u.arcsec).to(u.deg).value)
time=mjd.tdb.mjd #start time in mjd
time_jd=mjd.tdb.jd #start time in jd
f_p=eph1957.evaluate('F',time,t0par='PEPOCH')#pulse frequency
f_dot=eph1957.evaluate('FDOT',time,t0par='PEPOCH')
P_0=1./f_p #pulse period
P_1000=1000*P_0 #scale up to get output every 1000 periods
# orbital delay and velocity (lt-s and v/c)
d_orb = eph1957.orbital_delay(time)
v_orb = eph1957.radial_velocity(time)
# direction to target
dir_1957 = eph1957.pos(time)
# Delay from and velocity of centre of earth to SSB (lt-s and v/c)
posvel_earth = jpleph.compute('earth', time_jd)
pos_earth = posvel_earth[:3]/c.to(u.km/u.s).value
vel_earth = posvel_earth[3:]/c.to(u.km/u.day).value
d_earth = np.sum(pos_earth*dir_1957, axis=0)
v_earth = np.sum(vel_earth*dir_1957, axis=0)
#GMRT from tempo2-2013.3.1/T2runtime/observatory/observatories.dat
xyz_gmrt = (1656318.94, 5797865.99, 2073213.72)
# Rough delay from observatory to center of earth
# mean sidereal time (checked it is close to rf_ephem.utc_to_last)
lmst = (observability.time2gmst(mjd)/24. + mjd.lon/360.)*2.*np.pi
coslmst, sinlmst = np.cos(lmst), np.sin(lmst)
# rotate observatory vector
xy = np.sqrt(xyz_gmrt[0]**2+xyz_gmrt[1]**2)
pos_gmrt = np.array([xy*coslmst, xy*sinlmst,
xyz_gmrt[2]*np.ones_like(lmst)])/c.si.value
vel_gmrt = np.array([-xy*sinlmst, xy*coslmst,
np.zeros_like(lmst)]
)*2.*np.pi*366.25/365.25/c.to(u.m/u.day).value
# take inner product with direction to pulsar
d_topo = np.sum(pos_gmrt*dir_1957, axis=0)
v_topo = np.sum(vel_gmrt*dir_1957, axis=0)
#total relative velocity
total_rv = - v_topo - v_earth + v_orb
L=(1./(1+total_rv))#multiplying factor to find doppler frequency
f_dp=f_p*L #doppler shifted frequency
P_dp=1./f_dp #doppler shifted period
total_delay = d_topo + d_earth + d_orb
period=P_dp
return period
import numpy as np
from astropy.time import Time
from astropy.coordinates.angles import Angle
from astropy.constants import c
import astropy.units as u
import de405
import observability
from pulsar import ELL1Ephemeris
from barycentre import JPLEphemeris
import matplotlib.pyplot as plt
deg2rad = np.pi/180.
eph1957 = ELL1Ephemeris('psrj1959.par')
jpleph = JPLEphemeris(de405)
#********adjust 3 min for delay********
mjd = Time('2013-05-16 23:40:00', scale='utc').mjd
mjd = Time(mjd, format='mjd', scale='utc',
lon=(74*u.deg+02*u.arcmin+59.07*u.arcsec).to(u.deg).value,
lat=(19*u.deg+05*u.arcmin+47.46*u.arcsec).to(u.deg).value)
start=mjd.tdb.mjd #start time in mjd
time_jd=mjd.tdb.jd #start time in jd
end=(1+(3./60))/24 #length of observations (from timestamp files?)
finish=start+end #end time
delay=[] #empty array to hold delay times
original_delay=[] #empty array to hold delays
original_period=[] #empty array to hold the initial period for each time
doppler_period=[] #empty array to hold doppler shifted period
rv=[] #empty array to hold relative velocities of the system
def Period(current):
start = Time('2013-05-16 23:43:00', format='iso', scale='utc').mjd
current = start + (float(current) / (60 * 60 * 24))
eph1957 = ELL1Ephemeris('psrj1959.par')
jpleph = JPLEphemeris(de405)
mjd = Time(
current,
format='mjd',
scale='utc',
lon=(74 * u.deg + 02 * u.arcmin + 59.07 * u.arcsec).to(u.deg).value,
lat=(19 * u.deg + 05 * u.arcmin + 47.46 * u.arcsec).to(u.deg).value)
time = mjd.tdb.mjd #start time in mjd
time_jd = mjd.tdb.jd #start time in jd
f_p = eph1957.evaluate('F', time, t0par='PEPOCH') #pulse frequency
f_dot = eph1957.evaluate('FDOT', time, t0par='PEPOCH')
P_0 = 1. / f_p #pulse period
P_1000 = 1000 * P_0 #scale up to get output every 1000 periods
# orbital delay and velocity (lt-s and v/c)
d_orb = eph1957.orbital_delay(time)
v_orb = eph1957.radial_velocity(time)
# direction to target
dir_1957 = eph1957.pos(time)
# Delay from and velocity of centre of earth to SSB (lt-s and v/c)
posvel_earth = jpleph.compute('earth', time_jd)
pos_earth = posvel_earth[:3] / c.to(u.km / u.s).value
vel_earth = posvel_earth[3:] / c.to(u.km / u.day).value
d_earth = np.sum(pos_earth * dir_1957, axis=0)
v_earth = np.sum(vel_earth * dir_1957, axis=0)
#GMRT from tempo2-2013.3.1/T2runtime/observatory/observatories.dat
xyz_gmrt = (1656318.94, 5797865.99, 2073213.72)
# Rough delay from observatory to center of earth
# mean sidereal time (checked it is close to rf_ephem.utc_to_last)
lmst = (observability.time2gmst(mjd) / 24. + mjd.lon / 360.) * 2. * np.pi
coslmst, sinlmst = np.cos(lmst), np.sin(lmst)
# rotate observatory vector
xy = np.sqrt(xyz_gmrt[0]**2 + xyz_gmrt[1]**2)
pos_gmrt = np.array([
xy * coslmst, xy * sinlmst, xyz_gmrt[2] * np.ones_like(lmst)
]) / c.si.value
vel_gmrt = np.array([
-xy * sinlmst, xy * coslmst,
np.zeros_like(lmst)
]) * 2. * np.pi * 366.25 / 365.25 / c.to(u.m / u.day).value
# take inner product with direction to pulsar
d_topo = np.sum(pos_gmrt * dir_1957, axis=0)
v_topo = np.sum(vel_gmrt * dir_1957, axis=0)
#total relative velocity
total_rv = -v_topo - v_earth + v_orb
L = (1. / (1 + total_rv)) #multiplying factor to find doppler frequency
f_dp = f_p * L #doppler shifted frequency
P_dp = 1. / f_dp #doppler shifted period
total_delay = d_topo + d_earth + d_orb
period = P_dp
return period