How to Declare Orbital Elements in a File?

It is possible to define asteroid and comet orbital elements directly in the Asteroid and Comet tool. However, it is useful in some cases to directly define these orbital elements in a text file which is produced either automatically or manually. C2A supports the main orbital element formats: MPC, Bowell, TheSky and IAU, but it also owns its own format. A C2A orbital element file must have the extension ".c2a". The syntax of the C2A orbital elements is the following:

Asteroids

asteroid orbit, "<name>", <num>, <a>, <e>, <incl>, <node>, <peri>, <epoch>, <M>, <H>, <G>

<name> Object name
<num> Object number (-1 if not defined)
<a> Semi-major axis in AU
<e> Eccentricity
<incl> Inclination
<node> Longitude of the ascending node
<peri> Argument of perihelion
<epoch> Epoch of elements
<M> Mean anomaly at epoch
<H> Absolute magnitude
<G> Magnitude slope parameter

Comets

comet orbit, "<name>", <q>, <e>, <incl>, <node>, <peri>, <T>, <epoch>, <H>, <G>

<name> Object name
<q> Perihelion distance
<e> Eccentricity
<incl> Inclination
<node> Longitude of the ascending node
<peri> Argument of perihelion
<T> Time of perihelion passage
<epoch> Epoch of elements
<H> Absolute magnitude
<G> Magnitude slope parameter

If magnitude parameters H and G are not known, the value -1000 must be used in the declaration.

Examples

asteroid orbit,"Ceres",1,2.769130,0.07651618,10.594230,80.330211,72.018639,2456300.500000,306.620134,3.34,0.12
asteroid orbit,"Pallas",2,2.771614,0.23144033,34.839319,173.124036,309.979080,2456300.500000,288.655008,4.13,0.11
asteroid orbit,"Juno",3,2.670920,0.25529600,12.978971,169.887244,248.287909,2456300.500000,235.081728,5.33,0.32

comet orbit,"C/1995 O1 (Hale-Bopp)",0.914891,0.99493000,89.558900,282.087700,130.629100,2450538.162400,2456319.500000,-2.00,4.00
comet orbit,"P/1996 R2 (Lagerkvist)",2.607657,0.31091600,2.599600,40.141400,333.595900,2455850.001300,2456319.500000,11.50,4.00
comet orbit,"P/1997 T3 (Lagerkvist-Carsenty)",4.227212,0.36469000,4.847100,63.155100,333.906400,2457150.000300,2456319.500000,13.00,2.00

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