Difference between revisions of "Using QL outputs"
(Created page with "== Overview == The QL Tool produces quick-look products, but there are some straightforward steps allowing users to use these as a starting point for their science quality re...") |
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| − | i.e. in python, to reproduce the same transformation:<br /> | + | i.e. in python, to reproduce the same transformation, one would do:<br /> |
from astropy.io import fits<br /> | from astropy.io import fits<br /> | ||
| + | |||
im2D = fits.getdata('image.fits')<br /> | im2D = fits.getdata('image.fits')<br /> | ||
| Line 27: | Line 28: | ||
fits.writeto('outimage.fits',im2D)<br /> | fits.writeto('outimage.fits',im2D)<br /> | ||
| + | This image could then be used for a fresh extraction using IRAF or the user's preffered package, and will be one-to-one pixel aligned with the [approximate] WLC from the 1D extracted arc. | ||
| + | |||
| + | |||
| + | In IRAF, the equivalent would be:</ br> | ||
| + | imcopy a0361665[-*,*] test.fits</ br> | ||
| + | imcopy test.fits[99:2146,*] out65.fits</br > | ||
| + | [Note the 1-based indexing] | ||
Revision as of 10:24, 22 December 2016
Overview
The QL Tool produces quick-look products, but there are some straightforward steps allowing users to use these as a starting point for their science quality reductions
Important Notes
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.
The exact values for these are stored in:
/usr/local/etc/qlgui/pars.json
"badMax0": 98,
"badMin1": 2145,
in python 0-based numbering.
i.e. in python, to reproduce the same transformation, one would do:
from astropy.io import fits
im2D = fits.getdata('image.fits')
im2D = im2D[:,-:] # flip x
im2D = im2D[:,98:2145] # trim
fits.writeto('outimage.fits',im2D)
This image could then be used for a fresh extraction using IRAF or the user's preffered package, and will be one-to-one pixel aligned with the [approximate] WLC from the 1D extracted arc.
In IRAF, the equivalent would be:</ br>
imcopy a0361665[-*,*] test.fits</ br>
imcopy test.fits[99:2146,*] out65.fits</br >
[Note the 1-based indexing]
