The images from the James Webb telescope are truly amazing. Even more amazing, is too see what they look like in the raw format recorded by the telecope's instruments before they are processed. The Toronto Star has a very detailed article that explains how astronomers process the raw data to produce the gorgeous images that we see. I found it interesting that the process is similar to what I would do in Adobe Lightroom for a poorly exposed picture from my camera although the pixel-by-pixel calibration is far beyond anything I could contemplate doing.
For all the meticulous precision that went into the JWST’s design and construction, the data coming from it, in its rawest form, is uneven.
Images have to be corrected for imperfections inherent in the cameras themselves.
Cosmic rays hitting the telescope can create static in the detectors of its cameras, which is corrected for, in part, by capturing multiple versions of the same image.
And even the pixels — the smallest photosensitive units of the telescope’s detectors — themselves have different sensitivities; one of the more than one million pixels in the JWST’s Mid-Infrared Instrument (MIRI), for example, might be more sensitive than its neighbour, and less sensitive than another neighbour.
Thankfully, the JWST engineers have a solution for that — a complete calibration map of how to compensate for the variations in each pixel in every instrument on the Webb telescope.
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