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I don't understand exactly why all space pictures are black and white. There are hi-res cameras that are smaller than a coin now available to consumers, so I c

I don't understand exactly why all space pictures are black and white. There are hi-res cameras that are smaller than a coin now available to consumers, so I can't even imagine what could be used by scientists. Is it because they need to be transmitted back to earth, and 1 channel would be better than 4?

jacquesm 10y ago
It's because monochromatic filters would allow for a much larger portion of the incident light to be captured than if there were multiple filters active in different wavelengths at the same time (which you would need for color photography). Those filters are typically wheels that are rotated mechanically.
- jwilliams 10y ago
  Yup - it's a higher priority to capture visible, infrared and ultraviolet. Plus, the design of Cassini design of Cassini started in the 1980s and many of the part decisions would have been made then - even then they would have favored rugged, tried-and true technology over anything cutting edge. Actual launch was 1997.
- nkkollaw 10y ago
  But wouldn't color allow to observe the features a lot better? To me you lose a lot of details when you remove the color (although I would think there isn't a lot of color in space).
  - jacquesm 10y ago
    Color isn't so much removed as it is filtered out to improve the sensitivity in other bands. By filtering out visible light (or least, most of it) other bands can be imaged with much higher sensitivity (but it is also possible just to filter out a visible band of the spectrum for imaging). Just like you can't see IR right now with the naked eye but you could see a BW print of an IR filtered image (that's a 'false color' image, technically that term should be reserved for images that show other wavelengths as colors that we can interpret). The same goes for UV. A lot of astronomical imaging is done in wavelengths we can not observe directly. Almost all those 'pretty color pictures from space' are false color images. Another important bit is that for the most part space is the same on that scale today as it is tomorrow, so if you want to make several images of the same object with different filters you usually can without much in terms of loss of opportunity. For some configurations and objects nearer to us that is more problematic but for objects further away time is on our side. The furthest example of this is radio telescopes, which image the sky using radio waves, waves so long that they are no longer called 'light'. And yet, we can make really nice images by shifting those radio frequencies to the visible spectrum allowing us to 'see' with radio waves.
    - nkkollaw 10y ago
      Good explanation, thanks.

jacquesm 10y ago

It's because monochromatic filters would allow for a much larger portion of the incident light to be captured than if there were multiple filters active in different wavelengths at the same time (which you would need for color photography). Those filters are typically wheels that are rotated mechanically.

jwilliams 10y ago
Yup - it's a higher priority to capture visible, infrared and ultraviolet. Plus, the design of Cassini design of Cassini started in the 1980s and many of the part decisions would have been made then - even then they would have favored rugged, tried-and true technology over anything cutting edge. Actual launch was 1997.
nkkollaw 10y ago
But wouldn't color allow to observe the features a lot better? To me you lose a lot of details when you remove the color (although I would think there isn't a lot of color in space).
- jacquesm 10y ago
  Color isn't so much removed as it is filtered out to improve the sensitivity in other bands. By filtering out visible light (or least, most of it) other bands can be imaged with much higher sensitivity (but it is also possible just to filter out a visible band of the spectrum for imaging). Just like you can't see IR right now with the naked eye but you could see a BW print of an IR filtered image (that's a 'false color' image, technically that term should be reserved for images that show other wavelengths as colors that we can interpret). The same goes for UV. A lot of astronomical imaging is done in wavelengths we can not observe directly. Almost all those 'pretty color pictures from space' are false color images. Another important bit is that for the most part space is the same on that scale today as it is tomorrow, so if you want to make several images of the same object with different filters you usually can without much in terms of loss of opportunity. For some configurations and objects nearer to us that is more problematic but for objects further away time is on our side. The furthest example of this is radio telescopes, which image the sky using radio waves, waves so long that they are no longer called 'light'. And yet, we can make really nice images by shifting those radio frequencies to the visible spectrum allowing us to 'see' with radio waves.
  - nkkollaw 10y ago
    Good explanation, thanks.