Every time you look at anything you are looking at the past. There is no such thing as the "present", it's indefinable. If you assign any kind of value to it, no matter how small, that value can be divided into a past and a future. In reality there is only the past (which we live in through our slow senses) or the future.
If you could manipulate how fast the past reaches your senses (via manipulation of gravity perhaps?) you could manipulate how far back you can see/hear into the past. That would be a type of time travel I would think.
There is the "moment". Which yes, you cannot define it, but that doesnt mean it does not exist.