pygaia/errors/astrometric.py
def properMotionError(G, vmini, beta, extension=0.0):
  """
  Calculate the proper motion errors from G and (V-I) and the Ecliptic latitude beta of the source.

  NOTE! THE ERRORS ARE FOR PROPER MOTIONS IN THE ICRS (I.E., RIGHT ASCENSION, DECLINATION). MAKE SURE
  YOUR SIMULATED ASTROMETRY IS ALSO ON THE ICRS.

  Parameters
  ----------

  G     - Value(s) of G-band magnitude.
  vmini - Value(s) of (V-I) colour.
  beta  - Value(s) of the Ecliptic latitude.

  Keywords
  --------

  extension - Add this amount of years to the mission lifetime and scale the errors accordingly.

  Returns
  -------

  The error in mu_alpha* and the error in mu_delta, in that order, in micro-arcsecond/year.
  """
  factor = errorScalingMissionLength(extension, -1.5)
  parallaxError = parallaxErrorSkyAvg(G, vmini)*factor
  return errorScalingFactor('muAlphaStar',beta)*parallaxError, \
         errorScalingFactor('muDelta',beta)*parallaxError
def properMotionError(G, vmini, beta, extension=0.0):
  """
  Calculate the proper motion errors from G and (V-I) and the Ecliptic latitude beta of the source.

  NOTE! THE ERRORS ARE FOR PROPER MOTIONS IN THE ICRS (I.E., RIGHT ASCENSION, DECLINATION). MAKE SURE
  YOUR SIMULATED ASTROMETRY IS ALSO ON THE ICRS.

  Parameters
  ----------

  G     - Value(s) of G-band magnitude.
  vmini - Value(s) of (V-I) colour.
  beta  - Value(s) of the Ecliptic latitude.

  Keywords
  --------

  extension - Add this amount of years to the mission lifetime and scale the errors accordingly.

  Returns
  -------

  The error in mu_alpha* and the error in mu_delta, in that order, in micro-arcsecond/year.
  """
  factor = errorScalingMissionLength(extension, -1.5)
  parallaxError = parallaxErrorSkyAvg(G, vmini)*factor
  return errorScalingFactor('muAlphaStar',beta)*parallaxError, \
         errorScalingFactor('muDelta',beta)*parallaxError
Calculate the proper motion errors from G and (V-I) and the Ecliptic latitude beta of the source.

  NOTE! THE ERRORS ARE FOR PROPER MOTIONS IN THE ICRS (I.E., RIGHT ASCENSION, DECLINATION). MAKE SURE
  YOUR SIMULATED ASTROMETRY IS ALSO ON THE ICRS.

  Parameters
  ----------

  G     - Value(s) of G-band magnitude.
  vmini - Value(s) of (V-I) colour.
  beta  - Value(s) of the Ecliptic latitude.

  Keywords
  --------

  extension - Add this amount of years to the mission lifetime and scale the errors accordingly.

  Returns
  -------

  The error in mu_alpha* and the error in mu_delta, in that order, in micro-arcsecond/year.