Panic over. It is not an alien race trying to get our attention (shame) – but an extremely variable, variable star! This little beauty is WY Cas lying just below the open cluster NGC7789 in Cassiopeia, and Noel created the animation from two separate images taken over a year apart.
It is extraordinary that by chance I imaged this one almost at the peak of its maximum and minimum about 18 months apart. I was saying recently that I don’t believe in coincidence – I’ve just changed my mind on that!
This star varies between something like magnitude 7 (brightest) and magnitude 14-15 (dimmest). I had absolutely no idea that stars varied over this enormous range – thank you Roger Pickard at the BAA for educating me 🙂
Click on the image below for a larger version showing the “flashing” variable star.