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How to find FWHM?

  1. Jan 31, 2011 #1
    I've been searching on google for minutes but couldn't find out a consistent way so far. I mean, it seems everybody has something to say about it :)

    My data consists of pixel values (ADU's). I am writing a script to obtain fwhm of seeing disk.

    By definition of the gaussian curve, i should only calculate the standart deviation of these values theni get fwhm=stdev*2.355 .
    Am I correct?

    Or should i obtain a gaussian fit then i calculate fwhm as its name suggests?

    Thanks in advance,
  2. jcsd
  3. Feb 1, 2011 #2


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    If you do it both ways, and the answers are different, what does that tell you about the fitting algorithm that you used?
  4. Feb 9, 2011 #3
    for multiple sources on the same frame, should fwhm be same?
  5. Feb 10, 2011 #4


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    I would think the actual value of FWHM is less important than the rate of change near perfect focus.
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