[AstroPy] Reading in wavelength-calibrated spectra

Ian Crossfield ianc at mpia-hd.mpg.de
Tue Aug 14 11:47:35 EDT 2012


It's not quite what you're looking for, but I have Python code to 
generate a wavelength array from the "ec" echelle database IRAF generates:
http://www.astro.ucla.edu/~ianc/python/nsdata.html#nsdata.dispeval

Kelle's suggestion is probably the easiest, though likely not the fastest.

-Ian


On 8/14/12 5:10 PM, Kevin Gullikson wrote:
> Hi,
>
> I have some spectra that were reduced in iraf, and I would like to 
> read them in to python to do some fitting that I already have code 
> for. However, I am having trouble reading in the wavelength 
> calibration. The spectra are echelle, and the wavelengths are defined 
> with this thing in the header that looks like this:
>
> "
> WAT2_001= 'wtype=multispec spec1 = "1 32 2 10672.221264362 
> 0.086046403007761 20'
> WAT2_002= '46 0. 6.65 26.40 1. 0. 1 5 1. 2046. 10761.5346117191 
> 87.998952480064'
> WAT2_003= ' -1.32409633589482 -0.0165054046288388 
> -0.00680394594704411" spec2 ='
> WAT2_004= ' "2 33 2 10348.8582697 0.083445037904806 2046 0. 34.60 
> 58.07 1. 0. 1'
> WAT2_005= ' 5 1. 2046. 10435.4699172677 85.3379030819273 
> -1.2833101652519 -0.01'
> WAT2_006= '53518242619121 -0.0057861452751027" spec3 = "3 34 2 
> 10043.881872825 '
> ...
> "
>
> The numbers give the conversion from pixel coordinates to wavelength 
> coordinates.
> I was wondering if there was a python function that could correctly 
> read all that in, parse it, and give me a spectrum in flux vs 
> wavelength? I have tried playing with pywcs but that seems only to 
> work for images?
>
> Cheers,
>
> Kevin Gullikson
>
>
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-- 
Ian Crossfield
Max-Planck-Institüt für Astronomie

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