Can someone please clear up a little confusion I have?
I was always taught that light gathering power was purely a function of aperture of a scope. So a 8" scope will gather a lot more light than a 4" scope (presumably 4 x more, as it's actually about area of aperture).
But then I discovered about f/ratios and that a f/5 scope would be 'faster' (i.e. brighter) than an f/10 scope.
So now how do I factor that in?
Would an 8" scope which is f/10 still gather 4 x as much light as a 4" scope that is f/5 ?
In other words is light gathering ability only about aperture? In which case why is a f/5 4" scope faster (brighter) than a f/10 8" scope?
I'm not sure I am explaining my confusion clearly but I hope someone can see what I am getting at.