There is a couple of telescopes iv been looking at and im wondering what distances they can see in light years im pretty sure you can tell me by this informationg , one telescope has a magnitude of 20 and a redshift of 2 and another one was a magnitude of 17.5 i dont know the redshift tho , and the last one has a magnitude of 14.7 , i no big differnces , neways if anyone could tell me there seeing distance in light years roughly would be great thx.