Thursday, April 29, 2010

Hubble Space Telescope photographs: Are the colours real?

A question from a Byter: Would we see the same colours as are depicted in the Hubble photographs?

The short answer is no. The colour is added by NASA.

The longer answer is:
- The Hubble cameras record light from the universe with special electronic detectors. These detectors produce images of the cosmos not in colour, but in shades of black and white.
- Finished colour images are actually combinations of two or more black-and-white exposures to which colour has been added during image processing.
- Colour is added as a tool to enhance an object's detail, to visualise what ordinarily could never be seen by the human eye or to highlight interesting features of the celestial object being studied.\
- The colours added are a combination of red blue and green. Play around with the buttons at the following Hubble link to see how the combinations affect the final result:
- Click on this Hubble link and use the various buttons to see how the object looks when different photographic filters are used as is done when Hubble takes the photographs eg ultraviolet, green, red band infrared:
- See this link for another collection of Hubble pics (click on the pics to enlarge):

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