palRdplan
palRdplan
- Approximate topocentric apparent RA,Dec of a planet
- Description:
- Approximate topocentric apparent RA,Dec of a planet, and its
angular diameter.
- Invocation:
- void palRdplan( double date, int np, double elong, double phi,
double
ra, double
dec, double
diam );
- Arguments:
-
-
date = double (Given)
-
MJD of observation (JD-2400000.5) in TDB. For all practical
purposes TT can be used instead of TDB, and for many applications
UT will do (except for the Moon).
-
np = int (Given)
-
Planet: 1 = Mercury
2 = Venus
3 = Moon
4 = Mars
5 = Jupiter
6 = Saturn
7 = Uranus
8 = Neptune
else = Sun
-
elong = double (Given)
-
Observer's east longitude (radians)
-
phi = double (Given)
-
Observer's geodetic latitude (radians)
-
ra = double
(Returned)
-
RA (topocentric apparent, radians)
-
dec = double
(Returned)
-
Dec (topocentric apparent, radians)
-
diam = double
(Returned)
-
Angular diameter (equatorial, radians)
- Notes:
- Unlike with slaRdplan, Pluto is not supported.
- The longitude and latitude allow correction for geocentric
parallax. This is a major effect for the Moon, but in the
context of the limited accuracy of the present routine its
effect on planetary positions is small (negligible for the
outer planets). Geocentric positions can be generated by
appropriate use of the routines palDmoon and iauPlan94.