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How False Color Astronomy Works
StartsWithABang writes: When you look out at the nebulae in the night sky — especially if you're seeing them with your eye through a telescope for the first time — you might be in for a big surprise. These faint, fuzzy, extended objects are far dimmer, sparser and more cloud-like than almost anyone expects. Yet thanks to some incredible image processing, assigning colors to different wavelengths and adjusting the contrast, we can make out detailed structures beyond what even your aided eye could ever hope to perceive. Here's how the magic happens, and what it teaches us.
I know I should've expected it given it's on medium, and it's been submitted to /. by its own author, but that's a really bad article. It's full of irrelevant details, stupid comparisons and misleading crap. I understand the concept of "science evangelism" but could you please do it without acting like a total buffoon?
They are more art than science, providing an illusion of reality.
Nope, they are coded with the relation color = abundance of atomic component. Colors are a stimulus, they do not exist outside of all of our brains. What is real is the wavelength, and that, for instance, the transition of an electron from the 3rd to 2nd layer of the structure of the Hydrogen atom will emit a photon at 656nm, which we call red.
One disadvantage of the FITS format is that raw images typically need to be manipulated to show anything.
Nothing to do with the FITS format. That's the same type of information all RAW formats have : unprocessed data, as close as possible to the signal coming from the sensor after quantization, with ideally no processing, offset or other adjustments performed.
It made for great imagery, but wasn’t a true representation of how Jupiter looks.
Our vision is also subjective, it permanently adapt to lightning and ambient color conditions. There is no such thing as a true image representation. Especially in the mentioned case (a magazine), where it is desirable to have an image which pops the eye rather than a blob of washed out colors.
So what's the news here?
In the amateur astrophotography community some people image-process to death by using brush tools to selectively enhance specific features. An example: "Paint" a galaxy with a brush tool to make it stand out from the background. In my humble opinion, this is unacceptable. One other example: Wrong color balance in wide-field Milky Way shots, resulting in blue night skies. The night sky can't be blue for any aesthetic reason. At least, inform your viewers that your images are (heavy) processed.
Thierry Legault, an acclaimed astrophotographer says about image processing:
Furthermore, an astronomical image is something fragile, and it is dangerous (and unuseful) to torture it to extract details. Image processing softwares are now so powerful that they look like Ferraris...but don't drive them like Ayrton Senna ! Actually the best is to process an image as little as possible: the first quality of an amateur in this field is its moderation. Just take a look at the planetary images of the HST: they are detailed but very smooth and natural, no trace of the over-processing that damages so many amateur images. If a raw image is good, a slight processing must be sufficient for showing its contents. And if a processed image shows too few details, it is not a problem of processing but a problem of acquisition.
(From http://www.astrophoto.fr/ip.html)