irfpy.spice.spicetools

Misc tools related to SPICE

irfpy.spice.spicetools.set_error_action(strategy)[source]
Parameters

strategy – Strategy, ‘abort’, ‘report’, ‘return’, ‘ignore’, or ‘default’.

See SPICE document (erract_c()) for details.

irfpy.spice.spicetools.get_state(t, target, origin, frame, correction='NONE')[source]

Get the state of target from origin in frame.

Parameters

  • t – datetime object.

  • target – SPICE name of the target

  • origin – SPICE name of the origin

  • frame – SPICE name of the frame

  • correction – SPICE aberration correction

>>> get_state(datetime.datetime(2014, 10, 5, 3, 20, 15), 'MARS', "SUN", 'J2000', correction='LT+S')   
array([  8.39495688e+07,  -1.75490667e+08,  -8.27591341e+07,
     2.31543409e+01,   1.08699922e+01,   4.36065716e+00])
irfpy.spice.spicetools.state(t0, t1, dt, target, origin, frame, correction='NONE')[source]

Generator of the state vector.

Parameters

  • t0 – Start time

  • t1 – End time (exclusive)

  • dt – Time delta

  • target – SPICE name of target

  • origin – SPICE name of origin

  • frame – SPICE name of the frame

  • correction – SPICE aberration correction

Returns

Generator, yielding the tuple (t, pos, vel).

>>> t0 = datetime.datetime(2014, 10, 1, 12, 0)
>>> t1 = datetime.datetime(2014, 10, 1, 12, 10)
>>> dt = datetime.timedelta(minutes=2)
>>> for t, xv in state(t0, t1, dt, 'SUN', 'MARS', 'J2000', correction='LT+S'):       
...     print(t, xv[:3], xv[3:])
2014-10-01 12:00:00 [ -7.66126240e+07   1.78785069e+08   8.40721063e+07] [-23.50762679 -10.09017858  -3.99343982]
2014-10-01 12:02:00 [ -7.66154449e+07   1.78783858e+08   8.40716271e+07] [-23.50749856 -10.09047781  -3.99358053]
2014-10-01 12:04:00 [ -7.66182658e+07   1.78782647e+08   8.40711478e+07] [-23.50737033 -10.09077705  -3.99372125]
2014-10-01 12:06:00 [ -7.66210866e+07   1.78781436e+08   8.40706686e+07] [-23.50724209 -10.09107629  -3.99386196]
2014-10-01 12:08:00 [ -7.66239075e+07   1.78780225e+08   8.40701893e+07] [-23.50711385 -10.09137552  -3.99400267]
irfpy.spice.spicetools.get_position(t, target, origin, frame, correction='NONE')[source]

Get the position of target from origin in frame.

Parameters

  • t – datetime object.

  • target – SPICE name of the target

  • origin – SPICE name of the origin

  • frame – SPICE name of the frame

  • correction – Correction allowed by SPICE

irfpy.spice.spicetools.position(t0, t1, dt, target, origin, frame, correction='NONE')[source]

Generator of the position vectors.

Parameters

  • t0 – Start time

  • t1 – End time (exclusive)

  • dt – Time delta

  • target – SPICE name of target

  • origin – SPICE name of origin

  • frame – SPICE name of the frame

  • correction – SPICE aberration correction

Returns

Generator, yielding the tuple (t, pos).

>>> t0 = datetime.datetime(2014, 10, 1, 12, 0)
>>> t1 = datetime.datetime(2014, 10, 1, 12, 10)
>>> dt = datetime.timedelta(minutes=2)
>>> for t, x in position(t0, t1, dt, 'SUN', 'MARS', 'J2000', correction='LT+S'):       
...     print(t, x)
2014-10-01 12:00:00 [ -7.66126240e+07   1.78785069e+08   8.40721063e+07]
2014-10-01 12:02:00 [ -7.66154449e+07   1.78783858e+08   8.40716271e+07]
2014-10-01 12:04:00 [ -7.66182658e+07   1.78782647e+08   8.40711478e+07]
2014-10-01 12:06:00 [ -7.66210866e+07   1.78781436e+08   8.40706686e+07]
2014-10-01 12:08:00 [ -7.66239075e+07   1.78780225e+08   8.40701893e+07]
irfpy.spice.spicetools.get_velocity(t, target, origin, frame, correction='NONE')[source]

Get the velocity of target relative to origin in frame.

Parameters

  • t – datetime object.

  • target – SPICE name of the target

  • origin – SPICE name of the origin

  • frame – SPICE name of the frame

  • correction – Correction allowed by SPICE

irfpy.spice.spicetools.velocity(t0, t1, dt, target, origin, frame, correction='NONE')[source]

Generator of the velocity vectors.

Parameters

  • t0 – Start time

  • t1 – End time (exclusive)

  • dt – Time delta

  • target – SPICE name of target

  • origin – SPICE name of origin

  • frame – SPICE name of the frame

  • correction – SPICE aberration correction

Returns

Generator, yielding the tuple (t, vel).

>>> t0 = datetime.datetime(2014, 10, 1, 12, 0)
>>> t1 = datetime.datetime(2014, 10, 1, 12, 10)
>>> dt = datetime.timedelta(minutes=2)
>>> for t, v in velocity(t0, t1, dt, 'SUN', 'MARS', 'J2000', correction='LT+S'):       
...     print(t, v)
2014-10-01 12:00:00 [-23.50762679 -10.09017858  -3.99343982]
2014-10-01 12:02:00 [-23.50749856 -10.09047781  -3.99358053]
2014-10-01 12:04:00 [-23.50737033 -10.09077705  -3.99372125]
2014-10-01 12:06:00 [-23.50724209 -10.09107629  -3.99386196]
2014-10-01 12:08:00 [-23.50711385 -10.09137552  -3.99400267]
irfpy.spice.spicetools.get_distance(t, target, origin, frame='J2000', correction='NONE')[source]

Return the distance.

irfpy.spice.spicetools.distance(t0, t1, dt, target, origin, frame='J2000', correction='NONE')[source]

Generator for distance.

>>> for t, h in distance(datetime.datetime(2014, 10, 1, 15),
...                      datetime.datetime(2014, 10, 1, 16), datetime.timedelta(minutes=1),
...                      'MEX', 'MARS', frame='MSO'):  
...     print(t, h)
irfpy.spice.spicetools.get_sza(t, target, origin, frame='J2000', correction='NONE')[source]

Return the solar zenith angle in degrees.

irfpy.spice.spicetools.sza(t0, t1, dt, target, origin, frame='J2000', correction='NONE')[source]
irfpy.spice.spicetools.get_conversion_matrix(t, frame0, frame1)[source]

Return the frame conversion matrix (3x3)

If you want to convert from the MEX_SPACECRAFT frame to MSO frame, you may get a conversion matrix as follows.

>>> m = get_conversion_matrix(datetime.datetime(2014, 1, 23, 15, 30), 'MEX_SPACECRAFT', 'MSO')   
>>> print(m.shape)  
(3, 3)
irfpy.spice.spicetools.conversion_matrix(t0, t1, dt, frame0, frame1)[source]
irfpy.spice.spicetools.get_conversion_matrix_6d(t, frame0, frame1)[source]

Return the frame conversion matrix (6x6)

If you want to convert from the J2000 frame to IAU_MARS frame, you may get a conversion matrix as follows.

>>> m = get_conversion_matrix(datetime.datetime(2014, 1, 23, 15, 30), 'J2000', 'IAU_MARS')   
>>> print(m.shape)  
(6, 6)
irfpy.spice.spicetools.conversion_matrix_6d(t0, t1, dt, frame0, frame1)[source]
irfpy.spice.spicetools.et(t)[source]

Get the et from the datetime object.

Preparation. >>> import datetime >>> from irfpy.spice import localize >>> localize.furnsh_tls()

Execution. >>> print(et(datetime.datetime(2020, 1, 1))) 631108869.1839073

>>> print(et([datetime.datetime(2020, 1, 1), datetime.datetime(2020, 1, 2)]))
(631108869.1839073, 631195269.1839362)