get_rot_sky_pos

rubin_sim.utils.get_rot_sky_pos(ra, dec, obs, rot_tel)

@param [in] ra is the 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_tel is rotTelPos in degrees (the angle of the camera rotator). 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_tel will be associated with the corresponding ra, dec pair.

@param [out] rot_sky_pos 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).