not long, it's like lightning.. I saw the tendrils come down a bit with alternating red blue flashes reflecting in the clouds just like police car lights.. then it happened again but even bigger.. and then I saw the giant ring of red reflecting through the clouds just like the picture. I thought it was a UFO like in Close Encounters of the Third Kind. I got on the net (this was in 1995) and found some edu sites talking about this phenomenon but some people thought it was fiction. I assure you, it is quite real!
I've seen alternating Red Sprites and Blue Jets up inside a giant supercell twice during the same storm in the middle of Oklahoma where they have the most massive storms ever. It was a phenomenal experience .. at the time I thought it was a giant UFO!