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Data Format and Reduction


Gemini Data Format


All Flamingos-2 images are stored as MEFs. The extensions are:

[0]  Includes all the generic header information.


At this time there is a discrepancy between the UTEND and the actual time of exposure completion.  As a consequence, only UTSTART and EXPTIME provide reliable time information. This problem is planned to be corrected in the December 2015 software release.   All the affected archived files will be corrected backwards once the bug is fixed.

In the past there was a bug in the number of reads reported by the NREADS and LNRS. In all cases NREADS reports the actual number of pair (initial and final) non-destructive reads.  This bug is now fixed and the data at the archive were corrected in April 2015.  If you downloaded F2 data from the archive before that date the reported values in the ehader depended on the used readmode:

      LNRS=NREADS=1  for Bright Object mode

      LNRS=2, NREADS=4  for Medium Object mode

      LNRS=6, NREADS=8  for Faint Object mode 

For these data downloaded from the archive before April 2015, the header has to be corrected before using the F2 Gemini IRAF Package; otherwise the data will not be reduced correctly. The fixing script has already been made available to the PI’s; you can download it here.  Any questions, comments or suggestions for improvements of the script are welcome, and should be sent via a Helpdesk ticket.


[1]  This extension contains the data. But be aware that the number of the ADUs would depend on the number or reads. In all cases the data consists of the difference between the counts at the beginning and the end of the observation.

·       CDS (one read) = First Read - Last read

·       MDS (multiple reads) = Sum of the first reads  -  Sum of the last reads. In this case a MDS counts ~ Nreads * CDS counts 


Data Reduction


A first version of data reduction pipeline is available in the Gemini IRAF package, within the script.  The data reduction pipeline is intended for training and not for science quality processing.  The acompanying datasets can be downloaded here for the imaging and here for the spectroscopy examples.