reality

What we see is not what's out there for real. It's just our brains interpretation of the light reflecting from all those things we "see". Based on that interpretation we then make our mental image of the real world. 

What we see with our own eyes is what we accept as real. But we can only see up to a limited distance. We can extend that distance with optical devices like binoculars or telescopes. With them we can see surprisingly far in other places. With a good telescope even so far that we can see things relativistically from other times as well.