Nebulae, star clusters and brown dwarfs...

[Sum0]

If you're interested in going where no one has gone before in Celestia, then the January 2003 issue of Astronomy Magazine has a feature written by Phil Plait (he of Bad Astronomer fame) and iillustrated by Lynette Cook (she of astro-artist fame) about what a nebula, star cluster and a brown dwarf might look like up close, which might be interesting to incorporate into Celestia.
The actual article isn't available online, but there's a "making-of" at http://www.badastronomy.com/inprint/underalienskies.html.