How exactly can the Hubble Space Telescope see up to 15 billion light years? I've been researching about the Hubble Space Telescope on nasa.gov, and I've read that Hubble uses a digital camera to take pictures like a cell phone. That's all I've found so far. I can't find any information on how it can see so far away into space. Is the digital camera built to see billions of light years away, or does Hubble have some technology on it that allows it to zoom into the deep space?
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Hubble is a telescope.  This means it has a big mirror to gather light and focus it onto a small area, and a system of lenses and mirrors to magnify the image formed by the big mirror.
Now,  how far can you see? 100 miles? 1000?  You'd be way out!  The stars are already trillions of miles away.  Without a telescope you can see the Andromeda galaxy, which is 14 billion billion miles away.
You can see it because it is intrinsically very bright. Because it is so bright you can see it from far far away. If you had bigger eyes, you would be able to see things that are further away and dimmer.  And the Hubble telescope has a big &quot;eye&quot;
Hubble has one more trick: It does have a &quot;digital camera&quot; and it can use this to make a long exposure. This means that the light from a long period of time is allowed to accumulate on the light-sensitive chip. This means that even dimmer objects can be observed.
By a combination of a big mirror, and long exposures, Hubble is able to get a very deep view of very dim and distant objects.