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moozoo
2017-Nov-03, 05:39 AM
MPC have lots of comet orbits in parabolic orbit format.
e.g. http://www.minorplanetcenter.net/iau/MPCORB/CometEls.txt

How can I get the periodic ones in the best possible current elliptical orbit elements?
If I use parabolic orbital parameters then the outgoing comets (like Halleys) etc aren't going to be returning.
I'm aware comets aren't very predictable inside the frost line where they are out-gassing.

Do I need to look up each one, one by one in JPL's Horizons system?

Regards Michael

Centaur
2017-Nov-03, 06:08 PM
MPC have lots of comet orbits in parabolic orbit format.
e.g. http://www.minorplanetcenter.net/iau/MPCORB/CometEls.txt

How can I get the periodic ones in the best possible current elliptical orbit elements?
If I use parabolic orbital parameters then the outgoing comets (like Halleys) etc aren't going to be returning.
I'm aware comets aren't very predictable inside the frost line where they are out-gassing.

Do I need to look up each one, one by one in JPL's Horizons system?

Regards Michael

Try using the free Solex astronomical numerical integration program created by my friend Prof. Aldo Vitagliano in Italy: http://www.solexorb.it/

Add comets with @ symbol - then for a periodic comet enter its number followed by P, e.g. 24P (several can be listed together.)

Get the comet's Osculating Elements with X symbol.

The program may seem complicated at first, but read what appears on each page to navigate efficiently. Since the Version 12 manual is not yet available, also download Version 11 for a manual which will then appear as a Word file in the DOCS folder.

I just discovered this Version 12 today after seeing your request, and have had to learn some of the differences from Version 11 through trial and error.

Once you get the hang of it, Solex is marvelous and invaluable. It's also ultra-accurate due to the numerical integration method. Non-gravitational effects are automatically considered for comets - see options.

If you have questions about Solex, email Aldo at AlVitagl@unina.it

moozoo
2017-Nov-06, 06:40 AM
Try using the free Solex astronomical numerical integration program created by my friend Prof. Aldo Vitagliano in Italy: http://www.solexorb.it/
Add comets with @ symbol - then for a periodic comet enter its number followed by P, e.g. 24P (several can be listed together.)


Thanks for the reply Centaur.

Yes Solex is great and I use it a lot.
I also have Solex 12 and have corresponded with Aldo in the past.

I'm the author of the OpenCL Solar system gravitation simulation https://sourceforge.net/projects/openclsolarsyst/
It runs the whole solar system + 600,000 asteroids at 100fps+ with high precision (11+ order Integrator).
I use Solex's file format as an intermediate file format when importing the MPC asteroids. (all 600,000+)
I also use the authors relativistic corrections (with due credit)

I've used MPC observation data with Solex's companion program Exorb80 to add in single comets to my own runs from time to time.
However I was hoping to find an up to date source that has them all. ie Cartesian State Vectors for all know comets at the same Epoch as the MPC asteroid files.
So that I'd see this https://ssd.jpl.nasa.gov/?ss_outer in my own program.

Regards Michael