In going from the raw 2D images to the 1D extractions produce by the QL Tool:
* The x axis is flipped so that increasing wavelength runs in the same direction as increasing x
* The spectra are then trimmed to remove overscan, etc. Remember: the WLC is only good to a couple of A. No rectification or spectral tracing has been performed. The arc extraction is the single, ''central'' row, and may not correpsond to the same spatial location as your science target.
== For IRAF users ==
Since most observers seem to have their own scripts from the old version of the spectrograph, the easiest way to reduce the data is to use the QL wavelength -calibrated outputs as a reference for an IRAF reduction of the raw data.
This assumes familiarity with reducing longslit data in IRAF. Phil Massey's guide is an excellent reference: http://iraf.noao.edu/iraf/ftp/iraf/docs/spect.ps.Z
identifyAll.png|After matching ~5 lines, fitting, and pressing 'l' to auto-identify the rest
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* Once you have identified the lines in one aperture, repeat for every nth pixel (probably every 5th pixel is fine, the tilt is about 0.6 06 pixels per pixel) using '''reidentify'''.
* Run '''fitcoords''' on the database produced by reidentify
* Run '''transform''' on the image using the fitcoords database to produce a wavelength-calibrated, rectified 2D arc.
* This solution may now be copied to other images and science data extracted in the standard way!
<gallery>
transformArc.png|images pre(top)- and post(bottom)- rectification and WLC
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You may download the linelists used for the automatic wavelength calibration, or use your own: [[media:CuAr.lis|CuAr]], [[media:CuNe.lis|CuNe]]