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Spot-check the features

Before doing any wavelength calibration, it is beneficial to check how good your initial dewar offset file is, since the initial offset may be too large for align-mask to detect. To do this, we can run the spectral-lines program with the full HeNeAr.dat line list to produce a new file with the X and Y coordinates of the comparison lines for each slit:
spectral-lines -o CSIfld5 -l HeNeAr.dat -b 1 -e
Then we use display8 and tvmark in IRAF to display a mosaic of the lamp frames and overplot the positions from the resulting CSIfld5.xy file:
ecl> display8 ift0012 1
ecl> tvmark 1 CSIfld5.xy color=204
As you can see in Figure 2, the initial positions aren't too far off, so we can proceed to the next step of aligning the masks. If they don't seem close at all, you will need to use the adjust-offset routine to adjust the dewoff file. You may also need to alter the Disperser Misalignment with defineobs if you see a rotation offset in the positions.

Figure 2: Zoomed-in section of lamp mosaic displayed in ds9, with initial positions overplotted using the IRAF 'tvmark' routine.
Image spotcheck-sampleIMACS

Next: Aligning the masks Up: Running Sample IMACS data Previous: Setting up observation definition   Contents

Edward Villanueva 2014-08-27