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CIRPASS data reduction cookbook for data taken at the Gemini Observatory

This guide will be updated shortly, the SN1987a should be used until then, but noting the following.

The task dogemini should be used in place of the task docirpass. This task works with files named according to the Gemini convention, and converts them back to the cirpass convention for the cirpass pipeline. dogemini also has parameters to allow the default reduction to be changed and to reset the fibre position file used.

The first stage in reducing data from CIRPASS on Gemini, should be to make the appropriate fibre position file. This file is used to extract individual fibre spectra from the image, and its name is written to the image headers at an early stage of the processing (the header entry in the raw data will originally specifiy the file used at the telescope, this file will need to be recreated and the correct path to it set). Run dogemini on the appropriate calibration fibre observation with update set to no. This will produce a file called calfib_xxxx_ima.fits, which can be displayed using the mefdisplay task or with display calfib_xxxx_ima[sci,1] 1. The fibre position file can be created from the calfib_xxxx_ima.fits using the fibcal task. Further discussion on this task can be found in the SN1987a cookbook. The name of the fibre position file created should then be set as a dogemini parameter for all subsequent reductions, ensuring that the correct file is used from then on. Alternatively the EXTRFILE header entry should be manually updated for any subsequent _ima files produced.

The task read_header will print the header keywords that drive the pipeline data reduction, and has an option to load these headers into dogemini. This provides an easy way to manipulate the data reduction. Run read_header on the Gemini file, with update set to yes. Then epar dogemini and edit as required. Be sure to set the extrfile parameter to be the file output from fibcal above as the original will have been reloaded, also make sure that update is also set to yes for dogemini so that the new entries are written to the data when the task is run.

Andrew J. Dean. <ajd@ast.cam.ac.uk>
Last modified: Mon Mar 24 11:03:08 2003