Comment Re:A fantastic achievement (Score 4, Informative) 96
As the Universe is expanding, far away stars seem "redder" than closer stars.
As such, while JWST is partially "blind" for close stars, it can see the "red-shifted" and "infrared shifted" radiation generated.
Adding another sensor would make the alignment of mirrors even more complex than it is now, and the existing sensors were proven valuable enough not to be replaced.
Also, there is no value in putting an optical telescope in a Lagrange point. A new Hubble in Earth orbit would have been a small fraction of the cost.