Thanks for all your interesting comments and great pictures. One thing I wanted to comment on was how the display changed over perhaps 30 to 40 minutes. Initially I could see the usual green arc with some rays in it. Then it appeared to me that the arc swelled and moved southwards. This After this we began to see the larger and more colourful red/pink/purple rays and eventually Corona.
What are we seeing here? Is the auroral oval moving south as time progresses. Are the rays that we see overhead, the same rays seen in the green arc earlier? Is it because the oval has swept over our heads and the transition from green to red/pink/purple is just an effect of viewing angle? What do the experts say?