How to increase the visibility range through the dome sky model?

[Ginev]

I started the first stage of the making of my Tatooine map that i was preparing for 2 years so far.So i add a very big background planet surface model around my main ZERO EDITOR terrain.its working really good,however the problem is that when i go 5 000 meters in the sky and when i look forward there is some sort of visibility range that is not allowing me to see any further than let say 2000 meters.In the sky file i edited every parameter that is for PC.Visiblity range is 25 000 - 35 000 and the main visibility distance (which i was thinking will fix this) is also 20 000.However the problem is still there.I even made custom Dome sky (sphere models that is surrounding the whole world) but still cannot see further.If someone know a way please help me.Here is screen.Look how much only i am seeing forward.If i fly for a 2 minutes straight forward i am seeing the surface model but not when i am in the middle of the map.HELP!