Photo was taken not long after sunset, when the sky still had a significant blue tint (but yet stars were beginning to appear).
This is why there are more stars visible in the top (darker) than in the bottom (lighter).
The long star streaks are from two factors: a long focal length (232 mm) and distance from the North Star (lens is facing nearly perpendicular to it).
Please also see http://www.cambridgeincolour.com/tutorials/night-photography.htm.