Can you beat this one?

Text Structure & Purpose

A new telescope can pick out galaxies almost too faint to register, but that sensitivity has a cost. The same instrument also records light scattered by dust on its own optics, a haze spread across every exposure that engineers treated as random noise until 2021. Then they found that the haze is not random at all and that its pattern tracks tiny shifts in the alignment of the mirrors, so the unwanted signal now runs as a continuous check on the instrument that produces it.