How Much Telescope Time Should We Have?

How long would you need to focus on an area to get enough light so that you can actually see something? Is this, like you train the telescope at that spot in the sky for a year to collect the data? Or could it happen more quickly? If that's the kind of thing you're interested in, you would love to get a year of telescope time. We only know that the universe is expanding and accelerating because we have seen these cosmic candles, these typone supernova, go off through history as we look further and further into the past. That tells us how fast distant parts of space are moving away from us.