Well, their website seems to mention it'll work on Fedora 6.

That seems strange to me as Fedora is now at (11?) and is
usually (don't quote me) "backwards-compatible".

But anyway, you may want to try downloading the rpm file and
then using 'alien' via the command-line to convert it to a .deb file.

alien, is not typically installed by default, so you may want
to first check to see if you have it. At a terminal, you can type
which alien

and if it spits nothing back at you, then you don't have it in your system
and you can use synaptic GUI or the command-line installer
sudo apt-get install alien

Once you do have alien...

How to use it?
http://taufanlubis.wordpress.com/2008/01/22/alien-%E2%80%93-convert-rpm-to-deb-o\
r-deb-to-rpm/

Convert from RPM to DEB (alien -d)

sudo alien -d your-rpm-fileName

You are right, Why it shoult work on Fedora 6 and not on Fedora 11 I cannot
understand. Besides there is another (third)
way by tarfile, I would prefer. I will try your way expecting some probs!

When you try to install the .deb, or when you try to run it, it might say that
you need a library which is not installed on your system. If you are lucky, you
will be able to write down the name, and find it in Synaptic. But Scisoft does
say that the package depends on some things which are specific to Fedora. If
you don't mind wasting a couple of hours, it's probably worth a try.

I try to run the programm from a uncompressed tarball with no success.
Trying to run the programm by the setup.bash-file in the terminal I get the
following:

klaus@klaus-desktop:~$ sudo '/home/klaus/scisoft/bin/Setup.bash'
[sudo] password for klaus:
klaus@klaus-desktop:~$ '/home/klaus/scisoft/bin/Setup.bash'
/home/klaus/scisoft/bin/Setup.bash: line 347: return: can only `return' from a
function or sourced script
/home/klaus/scisoft/bin/Setup.bash: line 350: /usr/sbin/sestatus: No such file
or directory.
What does that mean??

If you run sestatus from the command line, Ubuntu will tell you what do do to
fix that error. I can't help with the "return" question.

I think I notice 2 things that are possibly at issue.

1. The terminal is trying to tell you about a missing part of your command line.
2. Second, there are spaces following some slashes in your command,
which can/will cause the shell to think you are requesting more than 1 file.

If I'm correct, you're trying to edit the file "Setup.bash", yes?

If so, you'd insert the name of an editor to use - following the "sudo" and
coming before the path of the file you wish to edit.

using your command as an example, --- and pretending you want to use "gedit"
- and removing the spaces.

klaus@klaus- desktop:~ $ sudo gedit '/home/klaus/scisoft/bin/Setup.bash'

I don´t edit the "Setup.bash".
What is missing in the commandline, I don´t know.
The Setup.bash has this description:
Setup script for the ESO Scisoft scientific software collection
#
# This file should be sourced using the sh/ksh/bash dot "." command
#
# . /scisoft/bin/Setup.bash
#
# by all users of the software. They should be no need to do anything else.
Maybee I run a wrong command? By the way I added the path of the file in the
".profile-folder" like this:
# ~/.profile: executed by Bourne-compatible login shells.

if [ "$BASH" ]; then
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
fi

mesg n

/home/klaus/scisoft/bin/Setup. bash

Scisoft as I see has many folders and softwares I think it´s a collection of
astronomy and about 1,1 GB.
I think Ubuntu cannot start them by my command, but I haven´t found another.