export iauAtco13
"""
ICRS RA,Dec to observed place.  The caller supplies UTC, site
coordinates, ambient air conditions and observing wavelength.

SOFA models are used for the Earth ephemeris, bias-precession-
nutation, Earth orientation and refraction.

This function is part of the International Astronomical Union's
SOFA (Standards of Fundamental Astronomy) software collection.

Status:  support function.

Given:
   rc,dc  double   ICRS right ascension at J2000.0 (radians, Note 1)
   pr     double   RA proper motion (radians/year; Note 2)
   pd     double   Dec proper motion (radians/year)
   px     double   parallax (arcsec)
   rv     double   radial velocity (km/s, +ve if receding)
   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   latitude (geodetic, 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:
   aob    double*  observed azimuth (radians: N=0,E=90)
   zob    double*  observed zenith distance (radians)
   hob    double*  observed hour angle (radians)
   dob    double*  observed declination (radians)
   rob    double*  observed right ascension (CIO-based, radians)
   eo     double*  equation of the origins (ERA-GST)

Returned (function value):
         int      status: +1 = dubious year (Note 4)
                           0 = OK
                           -1 = unacceptable date

Notes:

   1.  Star data for an epoch other than J2000.0 (for example from the
   Hipparcos catalog, which has an epoch of J1991.25) will require
   a preliminary call to iauPmsafe before use.

   2.  The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt.

   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 observed
   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. "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 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.

   12. 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, 2013
   iauAtciq     quick ICRS to CIRS
   iauAtioq     quick CIRS to observed

This revision:   2016 February 2

SOFA release 2018-01-30

Copyright (C) 2018 IAU SOFA Board.  See notes at end.
"""
# int iauAtco13(double rc, double dc,
#               double pr, double pd, double px, double rv,
#               double utc1, double utc2, double dut1,
#               double elong, double phi, double hm, double xp, double yp,
#               double phpa, double tc, double rh, double wl,
#               double *aob, double *zob, double *hob,
#               double *dob, double *rob, double *eo)

function iauAtco13(rc::Real, dc::Real, pr::Real, pd::Real, 
                   px::Real, rv::Real, utc1::Real, utc2::Real, 
                   dut1::Real, elong::Real, phi::Real, hm::Real, 
                   xp::Real, yp::Real, phpa::Real, tc::Real, 
                   rh::Real, wl::Real)

   # Allocate return values
   ref_aob = Ref{Float64}(0.0)
   ref_zob = Ref{Float64}(0.0)
   ref_hob = Ref{Float64}(0.0)
   ref_dob = Ref{Float64}(0.0)
   ref_rob = Ref{Float64}(0.0)
   ref_eo  = Ref{Float64}(0.0)

   status = ccall((:iauAtco13, libsofa_c), Cint, 
            (Cdouble, Cdouble, Cdouble, Cdouble,
            Cdouble, Cdouble, Cdouble, Cdouble,
            Cdouble, Cdouble, Cdouble, Cdouble,
            Cdouble, Cdouble, Cdouble, Cdouble,
            Cdouble, Cdouble,  
            Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble},
            Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), 
            convert(Float64, rc), convert(Float64, dc), 
            convert(Float64, pr), convert(Float64, pd), 
            convert(Float64, px), convert(Float64, rv), 
            convert(Float64, utc1), convert(Float64, utc2), 
            convert(Float64, dut1), convert(Float64, elong), 
            convert(Float64, phi), convert(Float64, hm), 
            convert(Float64, xp), convert(Float64, yp), 
            convert(Float64, phpa), convert(Float64, tc), 
            convert(Float64, rh), convert(Float64, wl),
            ref_aob, ref_zob, ref_hob, ref_dob, ref_rob, ref_eo)

   return status, ref_aob[], ref_zob[], ref_hob[], ref_dob[], ref_rob[], ref_eo[]
end