The fact that you COULD observe it, doesn't mean you actually will. Thus, until you actually observe it yourself, your knowledge of reality is still coming through faith. For one, you believe that the person telling you these things actually knows what he is talking about, and also that he is not attempting to lie to you. I very much doubt that many could afford a telescope that could see Titan, and so their knowledge will never rise above a simple belief that the scientist knows better than he does and he is not deceptive.
Faith in a human being can go wrong, but, let's be honest, there just isn't enough time, nor talent, nor energy nor equipment to verify everything that the experts say. Our knowledge of these things comes through hearing them from others, and thus implies at least a rudimentary faith in their competence and veracity. I might add that the confidence we have in the findings of others is necessary for the progress of human knowledge. No one would get very far if each of us had to rediscover calculus or remeasure the basic physical constants of the universe. It is faith in the metaphysical assumptions of truth, veracity and verifiability that make science possible, but the large corpus of observation is largely based on confidence in another human being.
I might add that the criteria of 'duplication' in many of the most advanced areas of physics are close to impossible for all but a very select few. Not everyone can build a hadron collider in their backyard....