HDRI Dome for sky not sharp - asking for advice

gamerhostonline

hello,

i'm trying to use the Orestes Iray HDRI skydomes for a basic scene with 2 trees and the backdrop of the night sky

the trees render crystal clear but the night sky even though it's supposed to be 18000x7000 shows very blury and low quality

does anyone know how i can render so that the dome output is sharp and clear ? 

example of poor night sky but clear trees attached

 

any advice where to look is appreciated

i have got a groundplane and i have also tried it out as far as it will go to try get the night in focus but nothing seems to work