get_rot_tel_pos

rubin_sim.utils.get_rot_tel_pos(ra, dec, obs, rot_sky)

@param [in] ra is RA in degrees. Can be a numpy array or a single value. (In the International Celestial Reference System)

@param [in] dec is Dec in degrees. Can be a numpy array or a single value. (In the International Celestial Reference System)

@param [in] obs is an ObservationMetaData characterizing the telescope pointing and site.

@param [in] rot_sky is rot_sky_pos in degrees (the angle of the field of view relative to the South pole given a rotator angle). Can be a numpy array or a single value. If a numpy array, should have the same length as ra and dec. In this case, each rot_sky_pos will be associated with the corresponding ra, dec pair.

@param [out] rotTelPos in degrees.

WARNING: As of 13 April 2015, this method does not agree with OpSim on the relationship between rot_sky_pos and rotTelPos. This is due to a discrepancy between the time that OpSim uses as the MJD when calculating rotTelPos and the time that OpSim reports as being the actual expmjd of the exposure (rotTelPos is calculated at the beginning of the exposure; expmjd is reckoned at the middle of the exposure).