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Is this a false color image?

  1. Nov 21, 2004 #1

    DB

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  2. jcsd
  3. Nov 21, 2004 #2

    tony873004

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    Looks like it was taken through a Hydrogen-alpha filter.
     
  4. Nov 21, 2004 #3

    DB

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    So it's color is assigned to the emission of waveleghts? Hydrogen-Alpha wavelenghts?
     
  5. Nov 22, 2004 #4

    tony873004

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    I'm not sure. I've seen different color suns through hydrogen-alpha filters. Wish I could afford one :smile:
     
  6. Nov 22, 2004 #5

    russ_watters

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    Regardless of the type of filter, it will be just a picture of a bright light unless the exposure time and amount of light gathered are controlled correctly. I have taken a few photos of the sun using a fast camera setting and a telescope with a dime-sized hole in the lens cap. A better way is with a filter that simply reduces the amount of light let through.
     
  7. Nov 24, 2004 #6

    Nereid

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    It's likely a HeII image, taken by SOHO's Extreme Ultraviolet Imaging Telescope (example: http://nssdc.gsfc.nasa.gov/image/solar/eit_sl_304.jpg). If so, then it's definitely a filter (centred at 30.4 nm). The colours are false; IIRC, the technique is to choose two colours (plus black and white) and an intensity histogram - min intensity = black, max intensity = white, low intensity = dark red (for example), high intensity = pale yellow. I don't know how to create this in Photoshop, but it's quite simple to do in many other image processing apps.
     
  8. Nov 24, 2004 #7

    Phobos

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    Hmm. I'd go with Nereid on this. It looks a lot more like SOHO photos than H-alpha photos I've seen.
     
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