Celestia Forums

1. Does anyone know of a good Celestia add-on catalog that rerenders binary systems (even just major ones, though I know there are double star catalogs with piles more entries)? For example: Capella is a sextuple star, but users don't see all these. The reason I ask is because a lot of people using Celestia for a certain project may not be familiar enough with astrocartography to remember these.

2. Is there a way to create a link, from a webpage, that opens Celestia and takes them to a particular star system, preferably without having to install any add-ons first?

...so, no? LOL

I have incorporated about all the binary orbits into Celestia that are /completely/ measured. If you give me credible /published/ orbits of the systems that you are missing, I will be glad to incorporate them.

But NO "phantasy data" , please. If you don't care about scientific rigor, you may look for some add-ons, instead.

Capella is a sextuple star, but users don't see all these.

It should be easy to imagine that the 6 member-orbits AND the 6 masses of the Capella system have NOT been all measured...

That's why Celestia users don't see them....

Bye Fridger

I'm not sure what you mean by "rerender".
Do you mean "mark their positions on the sky"?
Writing a script to mark them is relatively easy to do and is left as an excercise for the student.

Celestia v1.4.1 includes catalogs of several hundred visual and spectrographic double stars, although maybe not the ones you want. (Remember that binary = two = double)

I don't think any STC catalogs have been made public of star systems with more than two components unless some are in exoplanets.stc. One or two triple systems are known to have planets.

A link on a Web page is called a URL. While running Celestia, you can type a Ctrl-C to cause Celeatia to record (in your computer's "clipboard") a URL which corresponds to your current viewpoint. You can then use Ctrl-V to paste that URL into the code for a Web page.

This is documented in the Celestia Users Guide, which is available on the Motherlode's documentation page. http://www.celestiamotherlode.net/

Ah, thanks for the link Seldon.

By rerender I mean a catalog update that takes some doublestar catalog, guesses the orbital elements according to whatever is currently known, and creates a system barycenter with the known components at semi- or not-very-accurate eyeballed distances. I am concerned mostly with having as many known double and multiple stars identified as being double or multiple (with eyeballed distances accurate to 50% or so), not with precise orbital data.

I suppose I am looking for "fantasy data"--I'm doing this for an online RP/sci-fi universe--and I was asking specifically about add-ons. Is there a meaning for "phantasy" (I am not familiar with that term) or is that a dysphemism?

I was offering no criticism for the lack of sketchy data in the default release. That's a good thing. I was asking if anyone knew of any place where I can find this sketchy data in a package large enough to be worth downloading. Most of y'all know much better than I do where things are in this community. Thanks for your comments.

StarSeeker wrote:Ah, thanks for the link Seldon.

By rerender I mean a catalog update that takes some doublestar catalog, guesses the orbital elements according to whatever is currently known, and creates a system barycenter with the known components at semi- or not-very-accurate eyeballed distances. I am concerned mostly with having as many known double and multiple stars identified as being double or multiple (with eyeballed distances accurate to 50% or so), not with precise orbital data.

I suppose I am looking for "fantasy data"--I'm doing this for an online RP/sci-fi universe--and I was asking specifically about add-ons. Is there a meaning for "phantasy" (I am not familiar with that term) or is that a dysphemism?

I was offering no criticism for the lack of sketchy data in the default release. That's a good thing. I was asking if anyone knew of any place where I can find this sketchy data in a package large enough to be worth downloading. Most of y'all know much better than I do where things are in this community. Thanks for your comments.

The distances are by far the smallest issue. You need the masses to determine the barycenter etc. Masses are not so easy to determine. You need the standard parameters that determine an elliptical orbit in space and time for EACH of the 6 stars! So for 6 stars this is A LOT of guessing.

Here is the required parameter set for just 1 member of a binary system



So multiply these parameters by a factor around 6 and add a few more parameters for the coordinates of the barycenter....

Bye Fridger

As I wrote, I know of no STC catalogs which have been published for multiple-star systems.

Many astronomers are fascinated by multiple-star systems and have published papers about their orbital parameters, but the effort required usually means that only one system is described in a paper, and often large errors are ascribed to many of their orbital parameters. This is particularly true for systems that have members with orbits which are quite a distance from the system's barycenter. The orbital periods of those outer stars can be thousands of years, so they're moving much too slowly for their parameters to be measurable with current technology.

Of course when illustrating a story, even poorly known parameters can produce a reasonable model of a stellar system, using Celestia's defaults for the unknown values.

A search through the literature may produce some usable results. The astro-ph section of arxiv.org should have some papers about multi-star systems.