Here's a new 1.2.4 EXE for Windows:
http://www.shatters.net/celestia/files/celestia-win32-1.2.4pre2.zip
This is just the EXE--you need to have already installed this package first:
http://www.shatters.net/celestia/files/celestia-win32-1.2.4pre1.exe
This fixes the disappearing distant stars bug, a galaxy rendering bug, and the massive slowdowns from ring and eclipse shadows that appeared on some systems. It's very likely that the new EXE also fixes the ringed planet crashes. There are some new script commands as well as support for precession rate, but without new data files these additions won't have any effect yet.
I didn't have a chance to put together a UNIX source package yet, but I'll try and do that tonight. My recommendation is that if you're a UNIX user (actually anyone with a compiler) and want the absolute latest source, you should pull down the source tree from SourceForge's CVS server--then you can get the latest changes without waiting for a new release at all.
--Chris