Thanks for your replies and interest,
By a Heightmap i simply mean, creating non-flat planet surfaces. For example one could read in a raw image file (grey scale) for earth, and parse it , assigning a different height value for each pixel, this would create contures and such, providing much nicer closeups.
Especially since afaik there is a hightmap available for mars, which would be just awesome to have implemented in celestia.
I understand that everyone wants all these features, particles and what not, but I can certainly sympathise with the developers, it must be a nightmare for them to be sorting though all this code.
I mean the celestia configure file is just short of 1 MB , 1MB of plaintext????
but the code looks nice and modular, ill play around with it some, Although some nice docs would be appreciated, hehe.
I had a look at that thread
http://www.shatters.net/forum/viewtopic.php?t=5842 and thats something similar to what I had in mind, but Im more interested in creating nice close ups rather than some type of normal/bump to improve 'distance' viewing. I think bump mapping looks better on closeups anyhow, It would be relatively easy to do that now that glsl is around, one could make very nice extreme close up bump maps or rock surfaces and such.
Ive been looking through celengine and it all seems nice, ill play around with it some more, I just hope I dont get lost too quickly O_o.
, especially considering the celestia code is quite large and im relitavely unexperienced at opengl O_o. A few pointers in the right direction would be appreciated 
