On openSUSE Leap/Tumbleweed:
sudo zypper addrepo https://download.opensuse.org/repositories/home:munix9:unstable/${VERSION}/home:munix9:unstable.repo
sudo zypper refresh
sudo zypper install celestia
Where VERSION is '15.4', '15.5' or 'openSUSE_Tumbleweed'.
See also the download package sites on OBS for celestia and celestia-data.
On other GNU/Linux distributions:
If you are running a distribution other than the ones we have mentioned, try the experimental portable AppImage (Also see Issue #333 on our GitHub):
wget -O celestia-1.7.0-git-x86_64.AppImage https://download.opensuse.org/repositories/home:/munix9:/unstable/AppImage/celestia-latest-x86_64.AppImage
chmod 755 celestia-1.7.0-git-x86_64.AppImage
Optionally create a portable, main version-independent $HOME directory in the same folder as the AppImage file:
mkdir celestia-1.7.home