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rocketsocks t1_iu5ax4l wrote

Reply to comment by herrbdog in 3,200 Megapixels: The World’s Largest Camera will be Complete in 2023 by M416_Lover

It's 1 channel per image not RGB, this camera doesn't have a mosaic filter on the sensor itself the way consumer digital cameras do. Like almost all scientific imagers it instead is monochromatic but uses filters that can be rotated into place through an automated mechanism. This provides higher resolution for each color channel while also allowing for adjustments to the exposure timing for each channel depending on how much light it passes (which is much more desirable from a scientific standpoint). This particular camera will have 5 wideband color filters covering the visible through near-infrared bands but it won't have an exact match of red, green, and blue color channels.

So an exposure of a particular patch of the sky in all color channels will actually look like 5 successive exposures (or 6 if there is an unfiltered pass) through each of the filters.

It will have 18 bits per pixel of dynamic range.

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herrbdog t1_iu5hxtd wrote

well then the files would be smaller... only 18 bits per pixel? well that's not that much actually (only 262,144 possible color values), but is probably sufficient for the data acquired. idk, i'm not an astronomer :(

so 6 channels, but only 3 bits per channel?

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rocketsocks t1_iu5js7y wrote

Every exposure is 18 bits per pixel, each channel is a separate exposure. So a full image of one patch of the sky would be either 5 or 6 individual exposures for each color channel (plus a clear exposure) which would be equivalent to 90 or 108 bits per pixel.

There isn't a 1:1 match of filter channels to RGB colors but for just the 3 color channels closest to RGB that would be the equivalent of 54 bits per pixel, or 18 quadrillion colors.

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herrbdog t1_iu5n0l0 wrote

GOT IT, thanks!!! (yeah i realise it doesn't convert directly to RGB then)

intense detail then.

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