echelle.ecidentify fwidth

Karsten Brogaard wrote on Jun 13, 2007

Hi,

what does IRAF use this parameter for and is it the base width or the FWHM? I find it strange that the wavelength calibration rms decreases when the parameter is increased. Thanks in advance.

Karsten

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Mike Fitzpatrick wrote on Jun 13, 2007

The 'fwidth' parameter is actually used as a centering width for a feature detection. Specifically, see the description of 'width' for the center1d() function used by that task (http://iraf.net/irafhelp.php?val=center1d&help=Help+Page)

Cheers,
-Mike

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Last post on Jun 13, 2007