These are nice. The last couple are a bit blurry. I found it helpful sometimes to scale the individual groups that make up the scenery mod. Or even bringing in the
group closer to the center will make it smaller, that way they are clearer. You might try added 2-3 small nebulas per map, instead of 1 big 1.
Just my 2 cents. I been working on scenery mods quite a bit. Even made one up that adds stars. The model is made up of about 100 small squares aranged in a big square.
Then there are about 30 bmp's with scattered stars. Only 5-8 per map. Of various colors. About 6 of the bmps have small nebulas or galaxies. Its something you need to see in game when you can
rotate your ship around.
I especially like the planet ones.