chandra_aca.transform.radec_to_eci

chandra_aca.transform.radec_to_eci(ra, dec)

Convert from RA,Dec to ECI.

The input ra and dec values can be 1-d arrays of length N in which case the output ECI will be an array with shape (N, 3). The N dimension can actually be any multidimensional shape.

Parameters:

ra

Right Ascension (degrees)

dec

Declination (degrees)

Returns:

numpy array ECI (3-vector or N x 3 array)