sofars 0.6.0

use super::{apco13, aticq, atoiq, IauAstrom};

///  Observed place at a groundbased site to ICRS astrometric RA,Dec.
///
///  The caller supplies UTC, site coordinates, ambient air conditions
///  and observing wavelength.
///
///  This function is part of the International Astronomical Union's
///  SOFA (Standards of Fundamental Astronomy) software collection.
///
///  Status:  support function.
///
///  Given:
///  ```
///     type   char[]   type of coordinates - "R", "H" or "A" (Notes 1,2)
///     ob1    double   observed Az, HA or RA (radians; Az is N=0,E=90)
///     ob2    double   observed ZD or Dec (radians)
///     utc1   double   UTC as a 2-part...
///     utc2   double   ...quasi Julian Date (Notes 3,4)
///     dut1   double   UT1-UTC (seconds, Note 5)
///     elong  double   longitude (radians, east +ve, Note 6)
///     phi    double   geodetic latitude (radians, Note 6)
///     hm     double   height above ellipsoid (m, geodetic Notes 6,8)
///     xp,yp  double   polar motion coordinates (radians, Note 7)
///     phpa   double   pressure at the observer (hPa = mB, Note 8)
///     tc     double   ambient temperature at the observer (deg C)
///     rh     double   relative humidity at the observer (range 0-1)
///     wl     double   wavelength (micrometers, Note 9)
///  ```
///  Returned:
///  ```
///     rc,dc  double   ICRS astrometric RA,Dec (radians)
///  ```
///  Returned (function value):
///  ```
///            int      status: +1 = dubious year (Note 4)
///                              0 = OK
///                             -1 = unacceptable date
///  ```
///  Notes:
///
///  1)  "Observed" Az,ZD means the position that would be seen by a
///      perfect geodetically aligned theodolite.  (Zenith distance is
///      used rather than altitude in order to reflect the fact that no
///      allowance is made for depression of the horizon.)  This is
///      related to the observed HA,Dec via the standard rotation, using
///      the geodetic latitude (corrected for polar motion), while the
///      observed HA and (CIO-based) RA are related simply through the
///      Earth rotation angle and the site longitude.  "Observed" RA,Dec
///      or HA,Dec thus means the position that would be seen by a
///      perfect equatorial with its polar axis aligned to the Earth's
///      axis of rotation.
///
///  2)  Only the first character of the type argument is significant.
///      "R" or "r" indicates that ob1 and ob2 are the observed right
///      ascension (CIO-based) and declination;  "H" or "h" indicates
///      that they are hour angle (west +ve) and declination;  anything
///      else ("A" or "a" is recommended) indicates that ob1 and ob2 are
///      azimuth (north zero, east 90 deg) and zenith distance.
///
///  3)  utc1+utc2 is quasi Julian Date (see Note 2), apportioned in any
///      convenient way between the two arguments, for example where utc1
///      is the Julian Day Number and utc2 is the fraction of a day.
///
///      However, JD cannot unambiguously represent UTC during a leap
///      second unless special measures are taken.  The convention in the
///      present function is that the JD day represents UTC days whether
///      the length is 86399, 86400 or 86401 SI seconds.
///
///      Applications should use the function iauDtf2d to convert from
///      calendar date and time of day into 2-part quasi Julian Date, as
///      it implements the leap-second-ambiguity convention just
///      described.
///
///  4)  The warning status "dubious year" flags UTCs that predate the
///      introduction of the time scale or that are too far in the
///      future to be trusted.  See iauDat for further details.
///
///  5)  UT1-UTC is tabulated in IERS bulletins.  It increases by exactly
///      one second at the end of each positive UTC leap second,
///      introduced in order to keep UT1-UTC within +/- 0.9s.  n.b. This
///      practice is under review, and in the future UT1-UTC may grow
///      essentially without limit.
///
///  6)  The geographical coordinates are with respect to the WGS84
///      reference ellipsoid.  TAKE CARE WITH THE LONGITUDE SIGN:  the
///      longitude required by the present function is east-positive
///      (i.e. right-handed), in accordance with geographical convention.
///
///  7)  The polar motion xp,yp can be obtained from IERS bulletins.  The
///      values are the coordinates (in radians) of the Celestial
///      Intermediate Pole with respect to the International Terrestrial
///      Reference System (see IERS Conventions 2003), measured along the
///      meridians 0 and 90 deg west respectively.  For many
///      applications, xp and yp can be set to zero.
///
///  8)  If hm, the height above the ellipsoid of the observing station
///      in meters, is not known but phpa, the pressure in hPa (=mB), is
///      available, an adequate estimate of hm can be obtained from the
///      expression
///
///            hm = -29.3 * tsl * log ( phpa / 1013.25 );
///
///      where tsl is the approximate sea-level air temperature in K
///      (See Astrophysical Quantities, C.W.Allen, 3rd edition, section
///      52).  Similarly, if the pressure phpa is not known, it can be
///      estimated from the height of the observing station, hm, as
///      follows:
///
///            phpa = 1013.25 * exp ( -hm / ( 29.3 * tsl ) );
///
///      Note, however, that the refraction is nearly proportional to
///      the pressure and that an accurate phpa value is important for
///      precise work.
///
///  9)  The argument wl specifies the observing wavelength in
///      micrometers.  The transition from optical to radio is assumed to
///      occur at 100 micrometers (about 3000 GHz).
///
///  10) The accuracy of the result is limited by the corrections for
///      refraction, which use a simple A*tan(z) + B*tan^3(z) model.
///      Providing the meteorological parameters are known accurately and
///      there are no gross local effects, the predicted astrometric
///      coordinates should be within 0.05 arcsec (optical) or 1 arcsec
///      (radio) for a zenith distance of less than 70 degrees, better
///      than 30 arcsec (optical or radio) at 85 degrees and better
///      than 20 arcmin (optical) or 30 arcmin (radio) at the horizon.
///
///      Without refraction, the complementary functions iauAtco13 and
///      iauAtoc13 are self-consistent to better than 1 microarcsecond
///      all over the celestial sphere.  With refraction included,
///      consistency falls off at high zenith distances, but is still
///      better than 0.05 arcsec at 85 degrees.
///
///  11) It is advisable to take great care with units, as even unlikely
///      values of the input parameters are accepted and processed in
///      accordance with the models used.
///
///  Called:
///     iauApco13    astrometry parameters, ICRS-observed
///     iauAtoiq     quick observed to CIRS
///     iauAticq     quick CIRS to ICRS
///
pub fn atoc13(
    type_: &str,
    ob1: f64,
    ob2: f64,
    utc1: f64,
    utc2: f64,
    dut1: f64,
    elong: f64,
    phi: f64,
    hm: f64,
    xp: f64,
    yp: f64,
    phpa: f64,
    tc: f64,
    rh: f64,
    wl: f64,
) -> Result<(f64, f64), i32> {
    let mut astrom = IauAstrom::default();
    let mut eo = 0.0;

    /* Star-independent astrometry parameters. */
    let j = apco13(
        utc1,
        utc2,
        dut1,
        elong,
        phi,
        hm,
        xp,
        yp,
        phpa,
        tc,
        rh,
        wl,
        &mut astrom,
        &mut eo,
    );

    /* Abort if bad UTC. */
    match j {
        Ok(_) => {}
        Err(e) => return Err(e),
    }

    /* Transform observed to CIRS. */
    let (ri, di) = atoiq(type_, ob1, ob2, &astrom);

    /* Transform CIRS to ICRS. */
    let (rc, dc) = aticq(ri, di, &mut astrom);

    /* Return OK/warning status. */
    Ok((rc, dc))
}