Celestia Forums

As far as I have understood, if you want to use Celestia with a different set of .SSC files, you have to shut it down, change the .SSC files and then restart the program.

Is the only solution to edit the .SSC files in the subfolder "extras" and "data" each time you want another set of .SSC files?

I wonder if it possible to inform Celestia about which .SSC files it should use by command line switches or some other trick, so you could create a shortcut to each set of .SSC files.

You are correct. That's the way it works.

Of course, you can have them all active at the same time.

Thank you Selden for a very fast answer.

What I have in mind was to use Celestia to demonstrate for example the phases of the moon in education. In a split window one can have the moon as seen from the earth in one window and the orbit of the moon around the earth in the second window. It can be done very nicely in a "universe" with only the sun, the earth and the moon, where the latter two have a radius 10 times the real value! But I then have to use a special .SSC file, which don't work with the standard set.

Is it possible to suggest to the developers of Celestia to consider including a command line switch where it is possible to specify the set (or folder of) .SSC file to use (overruling the standard set) in a future version? With my knowledge of programming it should not be difficult to include that.

That should already be possible by using the command-line option

where "celestiarootdir" is the appropriate root directory to use.

I've never used it, though, so I'm not sure of the format of the directory specification.

However, you also can have multiple installations of Celestia on a computer, each in a different folder, and each with a different set of SSCs and other catalogs.

Another way to display such things is to define appropriate planets around another star.

kramskov wrote:Thank you Selden for a very fast answer.

What I have in mind was to use Celestia to demonstrate for example the phases of the moon in education. In a split window one can have the moon as seen from the earth in one window and the orbit of the moon around the earth in the second window. It can be done very nicely in a "universe" with only the sun, the earth and the moon, where the latter two have a radius 10 times the real value! But I then have to use a special .SSC file, which don't work with the standard set.

You may want to have four views instead of two: the Moon as seen from Earth, Orbit of the moon around the Earth with the Sun at the top, and closeups of the Moon and Earth.

kramskov wrote:Is it possible to suggest to the developers of Celestia to consider including a command line switch where it is possible to specify the set (or folder of) .SSC file to use (overruling the standard set) in a future version? With my knowledge of programming it should not be difficult to include that.

The command line option exists in the latest version. I have used it before and it is very useful for switching from one set of files to another.

kramskov:

There is another way to do what you want. Celestia 1.4.0 now has the ability to load alternative cfg files. Inside each cfg file are lines that specify particular extras folders. Put one set of ssc files in folder 1, and another set in folder 2. Use the command line switch to change cfg files, which will change extras folders. It is similar to the --dir switch but a bit easier, since you can keep your files in one main Celestia folder, and simply change from one extras folder to another.

To do all this, do the following:

Copy celestia.cfg and paste the copy in the Celestia folder.
Change its name to something like "ssc file1.cfg"
Open that file and edit the extras directory lines as follows:

ExtrasDirectories [ "extras" ] - change this to read

ExtrasDirectories [ "extras", "my extras1" ] - or any other name

Create a new extras folder named "my extras1" and place any ssc files and add-ons you wish in it. Store it in the Celestia root folder, next to "extras"

Create a Windows shortcut to Celestia.exe (version 1.4.0 final)
Open the properties window of the shortcut and edit the target line to read:

"C:\Program Files\Celestia\celestia.exe" --conf ssc file1.cfg

Double-click that shortcut and Celestia will load with a different cfg file, calling a different extras folder. Your view will be whatever you want it to be. When it is time to change views to a different set of ssc files, simply close Celestia, and double-click on a different windows shortcut that has duplicated the steps above, but which opens a third cfg file (ssc file2.cfg), which calls a third folder of ssc files named "myextras2".

In my educational Activities, I imbed links to these Windows shortcut files inside my educational documents (written in MS Word). I click on the link, Celestia opens with any add-ons I wish. Half-way down the page, I click on another imbedded link and Celestia opens with a new set of add-ons.

FYI

Frank