Difference between revisions of "Using QL outputs"

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(Overview)
(Important Notes)
Line 16: Line 16:
 
i.e. in python, to reproduce the same transformation, one would do:<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 />
 +
import numpy as np
 
im2D = fits.getdata('image.fits')<br />
 
im2D = fits.getdata('image.fits')<br />
im2D = im2D[:,::-1] # flip x<br />
+
im2D = np.fliplr(im2D[:,::-1])[:,98:2145]<br />
im2D = im2D[:,98:2145] # trim<br />
+
 
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.
 
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.

Revision as of 11:54, 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
import numpy as np im2D = fits.getdata('image.fits')
im2D = np.fliplr(im2D[:,::-1])[:,98:2145]
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:
imcopy a0361665[-*,*] test.fits
imcopy test.fits[99:2146,*] out65.fits
[Note the 1-based indexing]

ZZZ interactive WLC examination in IRAF

ZZZ cl script for flipping images and attaching WLC to arcs