How do I change the Skybox horizon so the sunset is not visible at night?

Hello I’m having some trouble with my night because it has a dusk color on the horizon
[1]: http://i.imgur.com/zTvBbiZ.png
Does anyone knows how to remove it and make a darker night. Also, if not too much, I would like to know how do I make a night skybox and still have the sun (making a moon with low brightness).

EDIT: I changed the density on the Atmospheric Fog and know its darker, but I still have the problem with the moon

if you look at the BP_Sky_Sphere that is used by default in a test project, you will see that the sun is rendered using a colour and sphere mask mostly. Duplicating the two sun commented blocks as moon sections is a possible way to go.

You can create a second sphere mask and use a moon colour and follow the same kind of approach that is used for rendering the sun onto the material. This should get a second orb on your mesh. You can add a second directional light and move it in a similar fashion to how the sun directional light is moved. Make it start 180 degrees opposite from where the suns start location is and voila simple moon.

I solved this issue by altering the “Sky Colors” section in the Sky Spheres Material like the following (right click and open the images in a new tab if you want a bigger version) :

If you also want to fade out the clouds during night (they can be quite bright) add the following in the Material:

Basically just add a lerp which is dependent on the sun height for the Horizon Color.
If you want the same for your clouds just go ahead and do the same for the power output in the rim light section.