How far back in cosmic time can modern technology, like the JWST, effectively look when detecting supernovae light, compared to historical naked-eye sightings?

Answer

Billions of years

While naked-eye observations are limited to events across tens of thousands of light-years, the JWST is now capable of looking at events whose light has traveled for billions of years.

How far back in cosmic time can modern technology, like the JWST, effectively look when detecting supernovae light, compared to historical naked-eye sightings?
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