How to find FWHM?

  1. Hi,
    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,
    bugra
     
  2. jcsd
  3. EnumaElish

    EnumaElish 2,481
    Science Advisor
    Homework Helper

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

    chemisttree 3,723
    Science Advisor
    Homework Helper
    Gold Member

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