Hello!

I was wondering about the North star. How come we cannot see it below the equator? Since we invented celestial navigation we have used it to find North right, so we know it doesn't move around? Why then, when we moved below the equator, did we have to resort to using the southern cross for navigation? How did the southern cross work for 100s of years if there is no south? 

Im sorry if this post came off as rude, I'm genuinely just confused

Best Regards