Looking for ssc orbit data to xyzv converter.

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Janus
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Looking for ssc orbit data to xyzv converter.

Post #1by Janus » 29.06.2018, 17:35

Okay, I know this may sound a little odd.

I am seeking an existing tool that will take orbit data from an ssc file for an asteroid or comet, and generate an xyz(v) file from it.
I am hoping such a tool already exists.
I need to make several for some long period objects as part of a project I am working on.

Thank you.


Janus.

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toutatis
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Post #2by toutatis » 29.06.2018, 17:51

from an ssc file

is there a problem to make XYZV-file from TXT-file from "HORIZONS"???

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Janus
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Post #3by Janus » 29.06.2018, 18:32

My problem is I have no idea how to use it to do that.
I am so far unable to make sense of most of what I find on nasa sites.

I lack the jargon or other knowledge to make proper use of it, and to understand what it gives me both.
The over view does me no good without the underlying data.

Basically what I am after is a tool/utility that will take in closest approach to the sun, farthest distance from, tilt relative earth orbit plane, and time.
Then turn that into a set of coordinates(xyz, or I can convert RaDec/Dist if I have to) relative to either the sun, or the earth, in time steps of my choosing.

I am not afraid of paint by numbers level of directions. it is a start.
From there I am hoping to learn/understand more as I go.

I am not an astronomer, nor am I mathematician or physicist.
What I am is someone who is trying to take what I can do, to learn do something else.

I have no problems with data and patterns, my problem is jargon, or things named for people.
As long as it has a structure, I am fine, as long as I stick to the structure.
Throwing random labels at things just adds confusion for me.

So, is there a way to use the horizons site to generate a set of time stamped xyz coordinates at a chosen interval?
Even if they are earth relative, I can simply generate a set for the sun, then convert to SOL relative.

Thanks.


Janus.

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FarGetaNik M
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Post #4by FarGetaNik » 29.06.2018, 21:22

Janus, I have not used HORIZONS in a while, but I successfully created samples xyzv orbit files for dozens of spacecrafts and minor bodies. I guess everyone has their own way to effectively work with this data, but here is what I was doing.

Go on the HORIZONS homepage and change the setting as follows:
Ephemeris Type: Vector Table
Target Body: The celestial object you want to track.
Observer Location: Your coordinate origin. This is quite tricky and I hate how the systems handles it. You need to enter a code that defines your origin. The SSB is @0; the sun @Sol for example. Planets are their number from the sun followed by 99, so Jupiter would be @599. Moons are their parent planet's number followed by their number, so @607 would be Hyperion. Asteroids are @2 followed by theri 6 digit minor planet number, like @2000433 for Eros. The same works for comets with a 1 leading, but for some reason the numbering is off.
Time Span should be self-explanatory.
Table Settings: Pay attention to the units you want to use (kilometers or AU depending on your coordinate origin).
For Output I use the download/save option.

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Janus
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Post #5by Janus » 01.07.2018, 16:17

@FarGetaNik

A kindly soul sent me data from there.
Several formats, several different sets, along with the parameters that generated them, and some explanations of those parameters.
I am now less uninformed, not truly understanding yet, but less uninformed.
I learn/work primarily by starting with the data, and working my way up to formulas.

Thus sites such as horizons are really annoying for me.
All of the information/data is there, but nearly unreadable to me.
In the interests of precision, all the proper language is used.
Which for me does the same job as high grade encryption.

The data is well structured, but the randomness of things/formulas named after people impedes me, that is not how I work.
The strange letters used in formulas are no different, for if I do not know where those letters come from, they are just noise.
Made school so much fun, got the right answers, but low grades since I never knew its secret name.
The math/science was no problem, but I never knew/know what the formula/procedure is called.

What I really need is all that stuff with some diagrams, done in full out long hand, no shortcuts.
Which is part of what I am working on for self education.
In the mean time I continue to get by.

Back on point, looking over the data from Horizons, it is obvious it is all real world, meaning actual data.
What I am needing is to make an ideal two body orbit in xyz(v) format.
Just the sun, and a comet.
Then match dates to add planetary influences.
The point is to see if an ideal orbit will match a real orbit once I add in the influence of the planets.
Thus I will plot the ideal, the calculated, and the actual, all at the same time, to compare them.
Try turning up orbits to 10 from 1 in the celestia.cfg to get an idea of what I mean.

A while back I was helping someone with a project.
During that, I was looking at Halley's comet, and I noticed a double pattern in its gap time.
After comparing it several ways, using averages of up to eight passes, I was sure the double pattern was real.
The short pattern rapidly matched up to Venus:Halley's with ~371:3 resonance, not a perfect match, but close.
That left a longer pattern however, and nothing that really lined up.

I rapidly found the papers detailing Venus's influence, and waded my way through them.
I found them incomplete however, though that could be just me.
What they pointed to however, was a secondary influence.
They posited Jupiter for that influence, however, that is kind of a cop out given its mass, it also didn't line up very well.
Orbits are both a dance, and a piece of music.
They don't use the base or drums to correct the rhythm, the corrections are built into the structure, and tend toward subtle.

Given Halley's standard orbit as a starting point, I searched.
While I found no exact matches, I did find an interesting approximation.
A small thing spotted in 2004, 90482 ORCUS, often referred to as the anti Pluto, it is also in 3:2 resonance with Neptune.
It's orbit brings it within 10AU of Halley's at the outer and slowest edge of its orbit.
Their orbits also line up very well, having very similar properties over all.
The timing gives a resonance of Halley's:Orcus ~13:4, which appears to match the secondary pattern I see.

I freely admit I could be seeing ghosts however, there are always ghosts in the data, fake patterns that fall apart.
Much of my work is finding them, though so far, this feels real to me.

My intent is to use a custom compile of Celestia that lets me use a script to set the time, then dump the coordinates of the nine planets and the sun from Celestia's internal coordinate system, along with measurements to maintain calibration.
Start back in 240BC, run up to the expected sighting in 2061AD, with a resolution of one day.

Then calculate the gravitic effects from the planets on the same scale.
See how close the calculated from ideal orbit is to what I get.

I know this sounds a little nuts, but this is the sort of thing I do in my spare time.
I will of course play with the mass of the 90482 Orcus system to see what that does as well.
The idea that Neptune is effecting Orcus which effects Halley's, which is then effected by Venus, is amusing.
Which could tie Halley's orbit oddities to the difference between Neptune's and Venus's orbits, modulated or tied together by Orcus.
As said, I could very well be wrong, or chasing ghosts.

So, does anyone know of any tools to calculate an ideal orbit given the data in an SSC file?


Janus.


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