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First, all astronomy PR images are edited to look good to normal people. Sharpness is enhanced to bring out fine details and wavelengths are mapped to attractiv
by giantrobot 4y ago
First, all astronomy PR images are edited to look good to normal people. Sharpness is enhanced to bring out fine details and wavelengths are mapped to attractive colors to make an attractive composite. If you are a scientist working with data from Hubble or Webb you're working on the raw data and ignore the PR images entirely. The PR images are derived from the scientific data but they are not themselves scientific.
Both Hubble and Webb also take observations with fairly narrow filters. In a PR image these essentially grayscale images are mapped to a color channel, red, green, or blue. The wavelength mapped to the "red" channel might be a mix of 650nm and 600nm filters. This blend will not look like what your eye would see but makes for a pretty desktop wallpaper.
Webb in particular only sees in the IR bands which your eye can't see. Making a PR images from Webb images arbitrarily maps IR wavelengths to RGB channels.
That's not to say a researcher won't filter and process the raw data. But their goal is to extract useful scientific information and not just produce an attractive image. They'll spend more time looking at graphs from the raw data than the actual 2D array of pixels.
For instance, if you know the composition for an object you know what it's spectra should look like. If you compare that spectra to what's received you can calculate the red shift of every pixel. Doing this for the whole image can then let you tell the red shift of an entire object giving an idea of its proper motion relative to us. For say a nebula this can show how it's moving and give an understanding of its 3D structure even though the images are all 2D.
I don't mean to disparage the PR images. They can often be used to explain phenomena to non-experts (not that I'm an expert). But they're never really going to show what the human eye might see, most stellar objects would look like mostly diffuse white blobs even "up close". Most things emit a number of wavelengths which just mix and look white to us. It's only with narrow band filters that telescopes can actually pick out fine details of most objects.