Wouldn't you know it. Got the scope collimated on a star with the new bobs knobs (works really well once you know how they work), then put the off axis guider on and the camera, focused on Rigel with the mask. Finally set the scope on the target for tonight and got it all centred. Took off the mask and was just about to start taking photography, when I looked up and saw a mass of clouds. Within 2 minutes the whole sky was fully shrouded in white trouble. Thought it might be passing over and waited 10mins, then decided to pack up. Only thing I got done was collimate the scope.
Bit annoying but that's what you get when you have a long setup. Time for a drink
.
Paul