21
4.8
LOCAL_PLANET
short int local_planet (double tjd, body *ss_object, body *earth,
double deltat, site_info *location,
double *ra, double *dec, double *dis)
PURPOSE:
Computes the local place of a planet or other solar system body,
given the location of the observer.
INPUT
ARGUMENTS:
tjd (double)
TT (or TDT) Julian date for local place.
*ss_object (struct body)
Pointer to structure containing the body designation for the
solar system body (defined in novas.h).
*earth (struct body)
Pointer to structure containing the body designation for the
Earth (defined in novas.h).
deltat (double)
Difference TT(or TDT)-UT1 at 'tjd', in seconds.
*location (struct site_info)
Pointer to structure containing observer's location (defined
in novas.h).
OUTPUT
ARGUMENTS:
*ra (double)
Local right ascension in hours, referred to mean equator and
equinox of J2000.
*dec (double)
Local declination in degrees, referred to mean equator and
equinox of J2000.
*dis (double)
True distance from Earth to planet in AU.
RETURNED
VALUE:
(short int)
0...Everything OK.
>0...Error code from function 'solarsystem'.
Discussion:
See the discussion for function topo_planet. Function local_planet is identical to
topo_planet in input arguments and use. The local place is essentially the topocentric
place expressed in the coordinate system of standard epoch J2000.0.
