Need website links that have sky textures

I currently have an idea for a wad and already began working on it, the one thing I really need is a custom sky texture for a space setting I already know how to insert it into the wad but I just need some good quality sky textures...if theres a site that you know of that has it please drop me a link. I already checked on Realm667 and I don't think they have any sky textures.

Have you checked the archives? A quick search turned up Skypack 1, Skypack 2, Skypack 3, Beautiful Strange Doom Sky Pack, Rise of the Triad skies pack, Icesky, Lucius' Crazy Skys (version 2), NewDoom Skys - Doom II Version, Night Sky, Quake 2 Skys (Doom 2 Version) and Doom Starfield (version 2). Texture packs converted from other games also tend to include skies, so you might like to check some of those out as well.

haw do you add side skys