Not sure if you guys are aware of the site
http://hubblesite.org/newscenter/archive/releases/index/0/
I shows some interesting images that Hubble is seeing. The neat part I liked was the zoom able image function.
Click on "Carina Nebula" link the first one then click Zoom icon below the image. This has a very large image 4K. You can see and download from astronomical picture of the day http://antwrp.gsfc.nasa.gov/apod/
I just downloaded the add-on for this nebula and will see what it looks like in Celestia. Thought you might like to know.
Don
Hubble Site for viewing images
Hubble Site for viewing images
Don't know anything