Program NERS_RADEC  computes right ascension and declination,
as well as their time derivatives, in the barycentric celestial
coordinate system corrected for annual and  diurnal aberration at
the moment of time TIM_TAI for a station with coordinates in the
terrestrial crust-fixed coordinate system COO_TRS that observes
a source with given azimuth and elevation in the topocentirc
coordinate system AZ, EL. Elevation is considered with respect to
the normal to the reference ellipsoid. Vertical deflection is
not accounted. Optionally the elevation can be be corrected for
refraction.

This program can be used only for computation of right ascensions
and declinations of objects beyond the Solar system, such as stars
or a galaxies.

Usage: ners_radec date coo_trs az el [none|optic|radio]

where date is the date in YYYY.MM.DD_hh:mm:ss.sss format or now,
      coo_trs is the vector of station coordinates in the rotating
              crust-fixed coordinate system in meters,
      az      is the azimuth of the observed body in rad;
      el      is the elevation of the observed body in rad;
      [none|optic|radio] is optional computation of refraction:
                         none  -- not to account refraction,
                         optic -- to account refraction in optic
                                  range;
                         radio -- to account for refraction in
                                  radio range.
 
Units: radians for azimuth, elevation angle, right ascension, and
       declination; rad/s for their time derivatives.