End of my astronomical timelapse shows?

[Magmatic]

And another thing. It's IMPOSSIBLE to focus in the dark with this D3100. At least not with a 200mm. The timelapse was made with a 35mm. I focused on a somewhat distant house and then switched to manual. It kind of worked, but I still get the feeling the stars are a little out of focus.

I will have to try a manual lens that has a hard infinity stop. I hope the camera still does not try to monkey with the aperture.