The discovery of redshift in starlight from distant galaxies is generally attributed to Vesto Slipher, an American astronomer.

Here's a breakdown:

* Early Observations: Slipher, working at Lowell Observatory in the early 1900s, was studying the spectra of spiral nebulae (what we now know as galaxies). He noticed that the spectral lines in these nebulae were shifted towards the red end of the spectrum.

* Interpretations: While Slipher made the observations, he didn't fully understand the implications. It was Edwin Hubble, in the 1920s, who connected Slipher's observations with the expansion of the universe. Hubble showed that the amount of redshift was directly proportional to the distance of the galaxy, providing strong evidence for the expanding universe.

So, while Slipher made the initial discovery of redshift, it was Hubble who gave it its true significance.