Lunar Nether

Officially endorsed continuation here

https://www.curseforge.com/minecraft/mc-mods/lunar-nether-neo

Adds the Moon, without being a tech mod. The Nether's usual bedrock ceiling is replaced with a new layer of rock hiding an interesting landscape above. Nether Portals work as usual, but will connect to the lunar surface if built high enough in the overworld. 

Current Features: 

+ 1 new Biome: Outrocks
+ Several new world gen features
+ New stone type, including polished and cut variants 
+ 1 new Ore: Ilmenite, can be smelted into Iron, or blasted into Titanium 
+ 1 new material: Titanium, can make building blocks just like copper
+ Clock for moon phases, made from Titanium 
+Realistic day/night cycle at 1/8th speed of the overworld +Tinkers Construct support

Side effects of this mod: 
Mob farms cannot be built on the nether roof using vanilla methods because the biome is different and natural mob spawning is disabled in the new biome.
There's no bedrock on the top of the nether, meaning certain exploits that used this bedrock, like some wither cages, will be impossible.
Portals will not always spawn where you would expect, but still follow the same rules.
Attempting to use this mod in an existing world is untested and will almost definitely lead to odd results, but probably won't outright break anything.
This mod won't work with any mods that change the nether's world height, and may or may not work with ones that change the terrain in other ways. 
Most shaders will not work and will cause issues on the nether surface