This function can be confusing to use due to the input coordinate system being specified by a combination of two options. Use itrs_to_cirs() or itrs_to_tod() instead. You can then follow these with other conversions to GCRS (or whatever else) as appropriate.
This old way of incorporating Earth orientation parameters into the true equator and equinox is now disfavored. Instead, the pole offsets should be used only to convert between the Terrestrial Intermediate Reference System (TIRS) / Pseudo Earth Fixed (PEF) and the International Terrestrial Reference System (ITRS) going forward, e.g. via novas_app_to_hor() / novas_hor_to_app() or else wobble().
This function is no longer used internally in the library, and users are recommended against using it themselves, since SuperNOVAS provides better ways to convert between GCRS and CIRS using frames or via gcrs_to_cirs() / cirs_to_gcrs() or novas_transform() functions.
Member cio_location (double jd_tdb, enum novas_accuracy accuracy, double *restrict ra_cio, short *restrict loc_type)
This function is no longer used internally in the library. Given that the CIO is defined on the dynamical equator of date, it is not normally meaningful to provide an R.A. coordinate for it in GCRS. Instead, you might use cio_ra() to get the CIO location w.r.t. the equinox of date (on the same dynamical equator), or equivalently ira_equinox() to return the negated value of the same.
You should use the frame-based novas_app_to_hor() instead, or else the more explicit (less ambiguous) tod_to_itrs() followed by itrs_to_hor(), and possibly following it with an atmospheric refraction correction if appropriate.
This old NOVAS C function has a few too many caveats. It is recommended that you use make_itrf_observer(), make_gps_observer(), or make_observer_at_site() instead (all of which set default mean annual weather parameters for approximate refraction correction), and optionally set actual weather data afterwards, based on the measurements available. This function will be available for the foreseeable future also.
This old NOVAS C function has a few too many caveats. It is recommended that you use make_itrf_site() or make_gps_site() instead (both of which set default mean annual weather parameters for approximate refraction correction), and optionally set actual weather data afterwards, based on the measurements available. This function will be available for the foreseeable future also.
The functions that use this structure have been deprecated also. There is no compelling reason why users should want/need it otherwise.
Member readeph (int mp, const char *restrict name, double jd_tdb, int *restrict error)
This old ephemeris reader is prone to memory leaks, and lacks some useful functionality. Users are strongly encouraged to use the new novas_ephem_provider / novas_set_ephem_provider() instead, for dynamically configured implementations at runtime. This prototype is provided only to extend support for legacy NOVAS applications only, where an inplementation had to be linked always.
This function can be confusing to use due to the output coordinate system being specified by a combination of two options. Use itrs_to_cirs() or itrs_to_tod() instead. You can then follow these with other conversions to GCRS (or whatever else) as appropriate.