[The science behind this is very amazing. I've never heard of this concept before. What's also fascinating, is that really OLD astronomical observations from 300 and 600 years ago, helped scientists to get their estimates right. If they are right there's going to be something that everyone in the northern hemisphere can see. Whether it will be bright enough in the sky for us to see in SA I don't know. This guy thinks almost everyone will be able to see it. Jan]
Here’s the video: https://www.youtube.com/watch?v=W4z5ovC5kQA