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“True Colour” does not really mean much here because colour is a characteristic of visual perception, i.e., it a human observer construct. With that in mind, an

“True Colour” does not really mean much here because colour is a characteristic of visual perception, i.e., it a human observer construct. With that in mind, and disregarding the fact that it is impossible to directly observe, the colour of the Sun would be white because it is the dominant irradiance source around us and an observer would be logically be chromatically adapted to it. It is the reason why the standard illuminant in colour science is D65, i.e. a average spectrum of the sun going through our atmosphere.

aaron695 4y ago
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deleted 4y ago
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mncharity 4y ago
> does not really mean much here [...] impossible to directly observe As misconceptions are common around the Sun, sunlight, and colour, it can be helpful to crosscheck concepts by swapping the Sun for a more familiar object: a light bulb, display, wall, shirt, or elephant. Imagine an article about a newly energy-efficient light bulb, which included only false-color thermal and near IR images - "Look, less waste heat and wasted light!". Would it seem odd to suggest adding a true-color visible-light photo? What if the authors color graded such a photo to hide a less marketable, say greenish cast? Years ago, NASA did a traveling museum exhibit on the Sun with lots of colorful images, but not a single white Sun. Now imagine a traveling exhibit on elephants. With colorful thermal IR images of ears as radiators, and false-color images of skin parasite distribution (thus mud baths) and so on. But not a single grey elephant. How odd would that be? Presented with "A 5-year old asks: The Sun is a big hot ball... what color is the ball?", it's not uncommon for first-tier-U physical-sciences graduate students to answer with variations on "it doesn't have a color; it's lots of different colors; it's rainbow color", reflecting misconceptions around color perception. Which then might be probed with "A 5-year old asks: what color is that shirt?". "Why does the Sun shine? Fusion!" becomes "Why does the LED light bulb shine? Electricity!", highlighting the incompleteness. Another crosscheck is seeing how the non-uniform appearance of the Sun (limb darkening) is handled. With the edge/limb appearing darker and redder because of longer sight lines through cooler higher layers.

aaron695 4y ago

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deleted 4y ago

[deleted]

mncharity 4y ago

> does not really mean much here [...] impossible to directly observe As misconceptions are common around the Sun, sunlight, and colour, it can be helpful to crosscheck concepts by swapping the Sun for a more familiar object: a light bulb, display, wall, shirt, or elephant. Imagine an article about a newly energy-efficient light bulb, which included only false-color thermal and near IR images - "Look, less waste heat and wasted light!". Would it seem odd to suggest adding a true-color visible-light photo? What if the authors color graded such a photo to hide a less marketable, say greenish cast? Years ago, NASA did a traveling museum exhibit on the Sun with lots of colorful images, but not a single white Sun. Now imagine a traveling exhibit on elephants. With colorful thermal IR images of ears as radiators, and false-color images of skin parasite distribution (thus mud baths) and so on. But not a single grey elephant. How odd would that be? Presented with "A 5-year old asks: The Sun is a big hot ball... what color is the ball?", it's not uncommon for first-tier-U physical-sciences graduate students to answer with variations on "it doesn't have a color; it's lots of different colors; it's rainbow color", reflecting misconceptions around color perception. Which then might be probed with "A 5-year old asks: what color is that shirt?". "Why does the Sun shine? Fusion!" becomes "Why does the LED light bulb shine? Electricity!", highlighting the incompleteness. Another crosscheck is seeing how the non-uniform appearance of the Sun (limb darkening) is handled. With the edge/limb appearing darker and redder because of longer sight lines through cooler higher layers.