def get_cip(jd1, jd2):
"""
Find the X, Y coordinates of the CIP and the CIO locator, s.
Parameters
----------
jd1 : float or `np.ndarray`
First part of two part Julian date (TDB)
jd2 : float or `np.ndarray`
Second part of two part Julian date (TDB)
Returns
--------
x : float or `np.ndarray`
x coordinate of the CIP
y : float or `np.ndarray`
y coordinate of the CIP
s : float or `np.ndarray`
CIO locator, s
"""
# classical NPB matrix, IAU 2006/2000A
rpnb = erfa.pnm06a(jd1, jd2)
# CIP X, Y coordinates from array
x, y = erfa.bpn2xy(rpnb)
# CIO locator, s
s = erfa.s06(jd1, jd2, x, y)
return x, y, s
RPOM = erfa.pom00(XP, YP, erfa.sp00(DJMJD0, TT))
# Form celestial-terrestrial matrix (including polar motion).
RC2IT = erfa.rxr(RPOM, RC2TI)
print("celestial to terrestrial matrix (including polar motion)")
pprint(RC2IT)
print('''
===========================================
IAU 2006/2000A, CIO based, using X,Y series
===========================================
''')
# CIP and CIO , IAU 2006/2000A
X, Y = erfa.xy06(DJMJD0, TT)
S = erfa.s06(DJMJD0, TT, X, Y)
# Add CIP corrections.
X = X + DX06
Y = Y + DY06
print("CIP corrections")
print('X = %.17f\nY = %.17f\nS = %.17f' % (X, Y, S * R2AS))
# GCRS to CIRS matrix
RC2I = erfa.c2ixys(X, Y, S)
print("NPB matrix, CIO based")
pprint(RC2I)
# Earth rotation angle
ERA = erfa.era00(DJMJD0 + DATE, TUT)
RPOM = erfa.pom00(XP, YP, erfa.sp00(DJMJD0,TT))
# Form celestial-terrestrial matrix (including polar motion).
RC2IT = erfa.rxr(RPOM, RC2TI)
print("celestial to terrestrial matrix (including polar motion)")
pprint(RC2IT)
print('''
===========================================
IAU 2006/2000A, CIO based, using X,Y series
===========================================
''')
# CIP and CIO , IAU 2006/2000A
X, Y = erfa.xy06(DJMJD0, TT)
S = erfa.s06(DJMJD0, TT, X, Y)
# Add CIP corrections.
X = X + DX06
Y = Y + DY06
print("CIP corrections")
print('X = %.17f\nY = %.17f\nS = %.17f'%(X, Y, S*R2AS))
# GCRS to CIRS matrix
RC2I = erfa.c2ixys(X, Y, S)
print("NPB matrix, CIO based")
pprint(RC2I)
# Earth rotation angle
ERA = erfa.era00(DJMJD0+DATE, TUT)
(
(-0.9741704366519668, -0.2115201000882231, -0.0917583114068277),
(0.0036436589347388, -0.0154287318503146, -0.0066892203821059),
)
]
)
# era 2000A CIP.
r = erfa.pnm00a(tt1, tt2)
x, y = erfa.bpn2xy(r)
# Apply IERS corrections.
x += dx
y += dy
# SOFA CIO locator. */
s = erfa.s06(tt1, tt2, x, y)
# Populate the context.
astrom = erfa.apci(tt1, tt2, pvb, pvh, x, y, s)
# Carry out the transformation and report the results.
ri, di = erfa.atciq(rc, dc, pr, pd, px, rv, astrom)
reprd("ICRS -> CIRS (JPL, IERS):", ri, di)
# The same but with Saturn then Jupiter then Sun light deflection.
b0 = erfa.LDBODY(
(
0.00028574,
3e-10,
np.array(
(
# SOFA heliocentric Earth ephemeris.
pvh, pvb = erfa.epv00(tt1, tt2)
# JPL DE405 barycentric Earth ephemeris.
pvb = ((-0.9741704366519668, -0.2115201000882231, -0.0917583114068277),
(0.0036436589347388, -0.0154287318503146, -0.0066892203821059))
# era 2000A CIP.
r = erfa.pnm00a(tt1, tt2)
x, y = erfa.bpn2xy(r)
# Apply IERS corrections.
x += dx
y += dy
# SOFA CIO locator. */
s = erfa.s06(tt1, tt2, x, y)
# Populate the context.
astrom = erfa.apci(tt1, tt2, pvb, pvh[0], x, y, s)
# Carry out the transformation and report the results.
ri, di = erfa.atciq(rc, dc, pr, pd, px, rv, *astrom)
reprd("ICRS -> CIRS (JPL, IERS):", ri, di)
# The same but with Saturn then Jupiter then Sun light deflection.
b0 = erfa.LDBODY(
(0.00028574, 3e-10,
((-7.8101442680818964, -5.6095668114887358, -1.9807981923749924),
(0.0030723248971152, -0.0040699547707598, -0.0018133584165345))))
b1 = erfa.LDBODY(
(0.00095435, 3e-9,
