Serious answer: the sensors in telescopes and probes don’t work exactly like human eyes. They pick up a different range of frequencies than our cone cells in the first place, and don’t have the same sort of overlapping input curves. There’s a lot of tricks and techniques in converting an image into the same sort of thing we’d see with the naked eye. You can sorta think of it like translating Japanese into English; there’s no perfect formula and it requires some creative interpretation no matter what.
The popular images that get published all over are simplistic composites and never really reflect the actual data astronomers rely on, so that was never a hindrance to scientific progress. It suddenly made the news because a research group decided to reevaluate the old data and reinterpret it against calibrations from other equipment (e.g. Voyager probe vs. the Very Large Telescope here on Earth). There’s a general interest factor in “wow that looks so much different than the old pictures”, when the underlying data really hasn’t changed.
Furthermore, it’s not that the original scientists failed to produce true-color images. The original published images of Neptune had deliberately enhanced colors to better show some of the features of the cloud surface, and the description text of the images said as much. But that nuance was quickly forgotten and everybody just took the deep blue coloring to reflect the actual color of the planet, which spread to depictions of the planet everywhere.
Serious answer: the sensors in telescopes and probes don’t work exactly like human eyes. They pick up a different range of frequencies than our cone cells in the first place, and don’t have the same sort of overlapping input curves. There’s a lot of tricks and techniques in converting an image into the same sort of thing we’d see with the naked eye. You can sorta think of it like translating Japanese into English; there’s no perfect formula and it requires some creative interpretation no matter what.
The popular images that get published all over are simplistic composites and never really reflect the actual data astronomers rely on, so that was never a hindrance to scientific progress. It suddenly made the news because a research group decided to reevaluate the old data and reinterpret it against calibrations from other equipment (e.g. Voyager probe vs. the Very Large Telescope here on Earth). There’s a general interest factor in “wow that looks so much different than the old pictures”, when the underlying data really hasn’t changed.
Furthermore, it’s not that the original scientists failed to produce true-color images. The original published images of Neptune had deliberately enhanced colors to better show some of the features of the cloud surface, and the description text of the images said as much. But that nuance was quickly forgotten and everybody just took the deep blue coloring to reflect the actual color of the planet, which spread to depictions of the planet everywhere.