short int topo_planet (double tjd, short int planet, short int earth,
double deltat, site_info *location,
double *ra, double *dec, double *dis)
Computes the topocentric place of a planet, given the location of
TDT Julian date for topocentric place.
planet (short int)
Body identification number for desired planet.
earth (short int)
Body identification number for the Earth.
Difference TDT-UT1 at 'tjd', in seconds.
*location (struct site_info)
Pointer to structure containing observer's location (defined
Topocentric right ascension in hours, referred to true
equator and equinox of date 'tjd'.
Topocentric declination in degrees, referred to true equator
and equinox of date 'tjd'.
True distance from observer to planet at 'tjd' in AU.
>0...Error code from function 'solarsystem'.
This function computes the topocentric place of a planet or other solar system body (neglecting
atmospheric refraction) for the location specified by the argument
, for the time specified by the
. Note that
is the TDT time at which the topocentric place is to be computed. The
difference TDTUT1 (often called
T) is passed to the function via argument
. Values of
published in the annual Astronomical Almanac or can be obtained from the National Earth Orientation
Service (NEOS) home page on the World Wide Web (http://maia.usno.navy.mil/). The user's choice of
the version of solarsystem determines the values of the arguments
, which identify the
planet and the Earth, respectively. The source of the rectangular coordinates is, of course, also determined
by the version of solarsystem in use.