matvis.conversions.eci_to_enu_matrix

matvis.conversions.eci_to_enu_matrix(ha, lat)[source]

3x3 transformation matrix to rotate ECI to ENU coordinates.

Transformation matrix to project Earth-Centered Inertial (ECI) coordinates to local observer-centric East-North-Up (ENU) coordinates at a given time and location.

The ECI coordinates are 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)

Note: This is a stripped-down version of the eq2top_m function.

Parameters:

  • ha (float) – Hour angle, in radians, where HA = LST - RA.

  • lat (float) – Latitude of the observer, in radians.

Returns:

m – 3x3 array containing the rotation matrix for a given time.

Return type:

array_like