From completely clear to completely fogged out in an hour!

It’s been completely clear here for most of today so I was looking forward to another night of superb deep-sky imaging on the mini-WASP array.  Still clear at 7:30 p.m. but too light to start work.  Look outside at 8:20 p.m. and what do I see?  Well nothing basically – we’re completely fogged out!!  So what’s that all about then?  Oh well – nothing else for it – stick on some Simple Minds at full volume.