Solar System Live

[Weatherlawyer]

I am a complete newb with almost no idea about Linux, using Mageia 5 on a 64 bit desk top.
I have been using Solar System Live to try and measure regression (if that is the term for contra rotation?) can someone help me set up something similar so I can grab images at 24 hour steps, please?

[Weatherlawyer]

Forum name: Help Central
Description: Have a question about using Celestia? Check here first for FAQs and helpful advice.
Forum rules: Please help to make this forum more useful by checking the FAQs before posting! Keep it clean, keep it civil, keep it truthful, stay on topic, be responsible, share your knowledge.

I would like to do that but I am afraid my mental abilities can't cope with searching. It is difficult enough for me to cope with typing as spelling is no longer habit forming for me.

Is there someone out there that has pity on a lost humanoid sole, so far out of his space that he intrudes on the kindness of alien cultures?

[selden]

Here's a .celx script to do a framegrab and then advance Celestia's simulation date by one day. You'll have to set the initial viewing conditions manually.

Code: Select all

celestia:takescreenshot("jpg", "test")
tdbdate = celestia:gettime()
celestia:settime(tdbdate+1.0)


On my computer the framegrab is written to Celestia's home directory. The default directory probably is set when you first do a manual screengrab from Celestia's File menu. I'll leave it to you to find out for certain.

Note that as written, the time will advance by the amount of delay between your clicks on the .CELX script's icon. Doing the appropriate math to force the date to be a specific round number is left as an exercise for the student. Lua 5.1 documentation, including its math functions and operators, is available at https://www.lua.org/manual/5.1/


For more information about the .Celx instructions that I've used, see
https://en.wikibooks.org/wiki/Celestia/Celx_Scrip ... ua_Methods/CEL_command_capture
and
https://en.wikibooks.org/wiki/Celestia/Celx_Scrip ... X_Lua_Methods/CEL_command_time

[Weatherlawyer]

[mike@localhost ~]$ celestia:takescreenshot("jpg", "test")
bash: syntax error near unexpected token `"jpg",'
[mike@localhost ~]$ tdbdate = celestia:gettime()
bash: syntax error near unexpected token `('
[mike@localhost ~]$ celestia:settime(tdbdate+1.0)
bash: syntax error near unexpected token `tdbdate+1.0'

[John Van Vliet]

a no

that is a script you run

it is not 3 individual lines in the terminal

( THIS ALSO is the same on Microsoft os's )

also for very accurate orbital precision and rotation you really need to use the Naif spice data

Also WHY are you using 5 ???
Mageia 6 was released back in july, 5 months ago .

for an example READ!!! the "randstar.celx"

it is in your install location

DEFAULT IS
/usr/bin
/usr/share/celestia/scripts/randstar.celx

the text file "randstar.celx "

Code: Select all

-- Title: Travel to Randomly Picked Stars

obs = celestia:getobserver()
while 1 do
    nstars = celestia:getstarcount()
    index = math.floor(nstars * math.random())
    star = celestia:getstar(index)
    celestia:select(star)
    obs:goto(star, 10)
    wait(10)
end


the script language is even easier to use than Microsoft's "SomeName.bat" batch files

[selden]

To put it another way...
Celx scripts must be interpreted by Celestia, not by bash.

There are a variety of ways to tell Celestia to interpret a .celx script. Which ones work for you depends on how (or if) Celestia was "installed" on your computer (whether .celx file types have been associated with Celestia), how Celestia was compiled and built (whether or not your copy of Celestia recognizes appropriate command-line options), and what functionality is provided by the GUI that you're using to interact with Linux (what capabilities it provides for passing file specifications to running programs).

Here are some of the possibilities:

1. If Celestia was "installed," you can just select (double-click with the left-mouse-button) the icon of the .celx script file.

2. Use the operating system's options to manually associate Celestia with the .celx file type. Then you can select (double-click with the left-mouse-button) the icon of the .celx script file.

3. Run Celestia. Celestia's "File" menu usually includes the option "Scripts..." Use it to browse to the text file where you've stored the script.

4. Run Celestia. In the Linux GUI that you're using, drag-and-drop the icon representing the .celx script file onto Celestia's open window.

5. In a terminal window,
Add Celestia's directory to your PATH
cd to the directory containing the .celx script

type the commnd
celestia --url name-of.celx

[Weatherlawyer]

If I mange to learn what you are saying, will I be better off than plugging away one page at a time with fourmillab's ancient offering?
Because I already know the sheer attention span draining process that takes for someone who is recovering from stroke. But at least I get a page full of image I can use to show people.

Thanks for the *help*.


***

Why I am using Mageia 5 is that it works. I have all my files on it and I don't feel the need to do anything about that.

[John Van Vliet]

it will get easier with time

i was using MinGW ( a windows linux ) in 2001
and moved to fedora 4 in 2005 as my full time operating system

and well selden's are i believe "impeccable"

[Paradigmer]

This planetarium applet that can select SSB for centering in the chart is what I had been looking for. Great work!

Please advise how to create objects for the barycenters of the gas giants, such as the barycenter of Jupiter and Saturn, barycenter of Uranus and Neptune, barycenter of the four gas giants, etc.

Can a line be projected to the edges for the alignment of SSB and Sun?

p.s. search the forum for these but found nothing.

[selden]

I'm not sure what you mean by "how to create objects for the barycenters". Simply creating a barycenter object is "trivial".

In an SSC catalog they're created by including the statement
Class "invisible"
in the definition of an object. You then define other SSC objects orbiting around it.

In .STC catalogs they're created by using the statement
Barycenter "object name" {...}
You then define STC or SSC objects orbiting around it.

Specifying how barycenters move is another matter entirely and can be extremely difficult to do from scratch. It requires the solution of multi-body gravitational problems, taking into account the motions of all of the planets' moons. The results of such a calculation usually are in the form of polynomials with thousands of terms. For specific cases in the Solar System, the easiest way to do this is to use someone else's results. In particular, you can obtain appropriate xyz or xyzv ephemerides from the JPL HORIZONS database server. Or you can just depend on the "CustomOrbit" definitions for the planets' orbits built into Celestia. They use truncated VSOP87 Chebyshev polynomials (truncated at about 1000 terms).

[Janus]

I am going to take a guess here.

Are you looking to create a series of screen shots from the position of earth, looking outward toward a target.

For instance, from earth, facing and focused on Venus, then do snapshots every solar day for a period of time.

Such as a full Earth year focused and centered on Venus.

Then take these screen grabs, and import them into a program to create an animated gif, or via frames into a video.

In my fork I display the RaDec of everything which would give you the data if that is what you are looking for.
Sadly, mine is Windows only, but I am working on fixing that.
Linux and C/C++ are great mysteries to me, though I am stumbling my way out of the dark.

If I am on the right track, I may be able to help you.

I am making a version of my solar system tour DVD that includes an object year of star sighting of the planets.
It is a side project to my personal educational effort using Celestia.
Year of the target by the way, not ours, but I am still stuck on the scaling since Pluto's year is ~1500 times longer than Mercury's is.


Janus.

[Paradigmer]

"In an SSC catalog they're created by including the statement
Class "invisible"
in the definition of an object. You then define other SSC objects orbiting around it.

In .STC catalogs they're created by using the statement
Barycenter "object name" {...}
You then define STC or SSC objects orbiting around it." - Selden

Simply creating a barycenter object in Celestia 1.6.1. for its dynamic visual appreciation is what I was looking for. In its simple setup, I would like to view how this barycenter approximately revolves around the SSB.

I mean like the SSB could be found as an object in Celestia, I could not find the object for the barycenter of Jupiter and Uranus, thus was wondering could it be created as an object.

Am a total NewB to Celestia, so can you please show me the steps on how to create the barycenter of Jupiter and Saturn in it. Thanks in advance.

Added after 14 minutes 44 seconds:
"Are you looking to create a series of screen shots from the position of earth, looking outward toward a target." - Janus.

I was trying to perceive how the barycenters of the gas giants revolve around the SSB centric planetarium chart. Was doing this manually with a series of screen shots of Celestia, which was looking from space at above the north celestial pole of the Solar System.