[NeverEnough]

color works just fine

I know that sometimes, images are first sent in black and white to save on data, color is sent later.

Hubble apparently only does black and white. color images can be obtained using a technique involving two of its black and white images. But that is a telescope, probably not similar.

http://hubblesite.org/gallery/behind_the_pictures/meaning_of...

the comet could just be grey, not sure about that one.

[mnw21cam]

Also, cameras are much more sensitive and higher resolution if they are B&W. A colour camera has to have a bayer matrix filter in front of the pixels (or some other weird trick) which throws away a load of the light.

Generally, when telescopes want colour images, they will take several pictures with different filters in front of the telescope, then combine them. This is useful because you can have a wide selection of filters, including ones for specific science-related wavelengths, like hydrogen alpha, or oxygen emissions. A normal colour camera is limited to three filters.