from counts to wavelength????

Sparkles wrote on Sep 17, 2010

Hi Iraf Gods,

I'm really new to Iraf (on placement), and having some problems. I'm working on a _x2d file and trying to extract the spectra using apall, getting a plot and everything's fine. However I need the x-axis in terms of wavelengths not counts, x2d are already wavelength calibrated so is there a simple way of doing this??

I was trying to use identify - but if its already calibrated for wavelengths it seems like the wrong thing to do?

thanks Sam

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Mike Fitzpatrick wrote on Sep 17, 2010

Assuming that by '_x2d file' you mean the output of the X2D task when calibrating STIS data ..... I don't have any of this data but if it's just an image of some kind then try the WSPECTEXT task if you want to list the values or the SPLOT task to view the individual spectra. Most likely, the x-axis is given in terms of pixel number, 'counts' would refer to the intensity on the y-axis.

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Last post on Sep 17, 2010