What happened here - bright light source in one frame?

[Fegato]

When blinking through my subs just now, I spotted this frame (see below including before and after).  This was about 22.30, I was in bed, it's totally dark here and remote from the road etc.

Some sort of bright light source has affected one 30 second sub. Looks like it's coming from above the top of the frame. Could that be a super bright Geminid or other meteor?  Struggling to think of anything else apart from some stranger coming on to the property and shining a light into the scope (it's big and was literally pointing at the zenith at this point, so you'd need to at least climb on a chair to do that, which would be a bit weird).

 

[Clarkey]

Firework just our of frame maybe? I assume there are no security lights nearby.

[ONIKKINEN]

Any chance that car headlights could sweep the sky just above the scope? If there was a thin layer of fog that is not apparent naked eye it could look like this.

I often setup at car parks or slightly off a road and these things happen.

[ollypenrice]

It doesn't take much with a RASA!!! 

Olly

[Fegato]

Thanks all, sorry, I didn't see the replies at the time.  Fireworks very unlikely here (don't even see them on 5th November!), no security lights nearby, and roads are quite a way away, so car lights seem unlikely (particularly at zenith). Anyway, as Olly says, the RASA does pick up light quickly! I guess it's a mystery.