SuperNOVAS v1.2
The NOVAS C library, made better
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Data Fields
novas_orbital Struct Reference

#include <novas.h>

Data Fields

double a
 [AU] semi-major axis
 
double apsis_period
 [day] Precession period of the apsis, if known.
 
double e
 eccentricity
 
double i
 [deg] inclination of orbit to the reference plane
 
double jd_tdb
 [day] Barycentri Dynamical Time (TDB) based Julian date of the parameters.
 
double M0
 [deg] mean anomaly at the reference time
 
double n
 
double node_period
 [day] Precession period of the ascending node, if known.
 
double omega
 [deg] argument of periapsis / perihelion, at the reference time
 
double Omega
 [deg] argument of ascending node on the reference plane, at the reference time
 
novas_orbital_system system
 orbital reference system assumed for the parametrization
 

Detailed Description

Keplerian orbital elements for NOVAS_ORBITAL_OBJECT type. Orbital elements can be used to provide approximate positions for various Solar-system bodies. JPL publishes orbital elements (and their evolution) for the major planets and their satellites. However, these are suitable only for very approximate calculations, with up to degree scale errors for the gas giants for the time range between 1850 AD and 2050 AD. Accurate positions and velocities for planets and their satellites should generally require the use of precise ephemeris data instead, such as obtained from the JPL Horizons system.

Orbital elements describe motion from a purely Keplerian perspective. However, for short periods, for which the perturbing bodies can be ignored, this description can be quite accurate provided that an up-to-date set of values are used. The Minor Planet Center (MPC) thus regularly publishes orbital elements for all known asteroids and comets. For such objects, orbital elements can offer precise, and the most up-to-date positions and velocities.

REFERENCES:

  1. Up-to-date orbital elements for asteroids, comets, etc from the Minor Planet Center (MPC): https://minorplanetcenter.net/data
  2. Mean elements for planetary satellites from JPL Horizons: https://ssd.jpl.nasa.gov/sats/elem/
  3. Low accuracy mean elements for planets from JPL Horizons: https://ssd.jpl.nasa.gov/planets/approx_pos.html
Author
Attila Kovacs
Since
1.2
See also
object
enum NOVAS_ORBITAL_OBJECT
NOVAS_ORBIT_INIT

Field Documentation

◆ n

double n

[deg/day] mean daily motion, i.e. (GM/_a_3)1/2 for the central body, or 360/T, where T is orbital period in days.

The documentation for this struct was generated from the following file: