ptgori_to_quaternion

ptgori_to_quaternion(p_ptg_radec, p_ori, deg=False)[source]

Compute quaternion associated to rotation defined by a pointing direction and orientation

X instru axis is the pointing axis , ** CNES choice ** Z instru axis determine orientation in sky, not clear in CNES document, so it’s my choice Orientation of Z instru axis follow IAU recommandation to measure polarisation angle example:

  1. orientation is 0 so Z instru axis pointed to celestial North pole
  2. orientation is 90 deg so Z instru axis pointed following a parallel of celestial sphere with East direction
Parameters:
  • p_ptg_radec (list) – ra, dec
  • p_ori (number) – orientation angle with convention defined above
  • deg (boolean) – input angle in degree, default rad
Returns:

unit quaternion
Return type:

list/array of float