There are two ways to define "natural".

One way is as though you are moving the observer. You move (yourself) up to look up.

Another way is as though you are moving the object. You move (the scene) down to look up.

Both are perfectly natural in different contexts.

Everyone perfectly naturally turns their head up or lifts a telescope up in order to look higher.

Everyone also perfectly naturally slides a paper down or rorates a globe down in order to see higher parts of it.