u/yubla

Red is filter f444w-f470n, Hot H₂. Green is f187n, H⁺, blue is f115w, a general filter.
Credits: NASA, ESA, CSA, STScI.

A JWST image, filter f444w captures "Mab" area near supernova remnant Cassiopeia A. As the light propagates space it illuminates farther and farther regions of dust. Color here denotes the time JWST captured the light. Red is older from summer 2024 (four visits), and blue arrived us later, on July 2025.