matvis.conversions.point_source_crd_eq

matvis.conversions.point_source_crd_eq(ra, dec)[source]

Coordinate transform of source locations from equatorial to Cartesian.

This converts RA and Dec angles to a Cartesian x,y,z unit vector in an Earth-Centered Inertial (ECI) coordinate system aligned with the celestial pole, i.e. for (x,y,z) (RA=0 deg, Dec=0 deg) = (1, 0, 0) (RA=90 deg, Dec=0 deg) = (0, 1, 0) (RA=0 deg, Dec=90 deg) = (0, 0, 1)

The RA and Dec are assumed to be in a particular reference frame that may not match-up with standard frames like ICRS/J2000. To convert coordinates from a standard system into the relevant frame, see equatorial_to_eci_coords().

Parameters:

  • ra (array_like) – 1D arrays of source positions in equatorial coordinates (radians).

  • dec (array_like) – 1D arrays of source positions in equatorial coordinates (radians).

Returns:

Equatorial coordinates of sources, in Cartesian system. Shape=(3, NSRCS).

Return type:

array_like