This week's photo shows a cloudy sky above the head of the River Tay estuary, taken from the south bank. It must be low tide, the effect of which can be felt as high up as the city of Perth. At this time the mud flats, frequented by flocks of geese at this time of year and the reed beds, formerly supplying material for roof thatching, can be clearly seen. Believe it or not, smallish cargo boats can still navigate a channel through all of this up to Perth harbour.
For more sky pictures look at the Skywatch Friday site.