[News] Some issues

[Luiz DaCosta]

Mark

I wonder if you would be interested in coming to ESO and getting a demo
from B. Vandame using the C-library only for the same data which we 
could ftp
to ESO - I would be very interested

Luiz

Dr. Mark Neeser wrote:

>Hello All,
>
>As a test of data reduction routines (astro-wise vs. Bonn pipeline vs.
>IRAF) we have immersed ourselves (primarily Jan Snigula and
>Yuliana Goranova) in the astro-wise pipeline using our WFI data.
>
>Here some results/comments:
>
>- Dataset used for testing: WiFI- images taken over 6 nights
>  (approx. 50GB).
>
>  Time for testreduction: approx. 1 week (most of the delays were caused
>  by unannounced pipeline changes occurring during the reduction.
>
>Details:
>
>- COSMICFILTER:
>  We tried to implement our cosmic filtering routine (cosmicfits from
>  Claus Goessl) in the pipeline. This attempt failed, due to the
>  current handling of bad columns/pixels in the images and the
>  existance of negative pixel values. The latter problem can be
>  circumvented in the program call, but the bad columns/pixels would
>  need to be replaced (PRIOR to executing our cosmic filter routine) with
>  a well defined NaN value, e.g. 0.  Essentially, our cosmic filter
>  routine treats the bad columns as cosmic rays and spends an inordinate
>  amount of time trying to detect/correct them.  It would be easy to
>  mask these as NaN's prior to running "cosmicfits".
>
>- BAD COLUMNS:
>  Bad colums in general must be taken care of at an earlier stage of
>  the pipeline than currently implemented (see example ps
>  file). This was already discussed by Mark and Roeland.
>
>- SWARP:
>  The pipeline currently uses a beta version of Swarp (swarp 2.0b),
>  that fails to create usable weight images.  Reasonable weight
>  images are essential for obtaining a fast run-time with cosmicfits,
>  and are crucial when the frames on which cosmic rays are detected
>  have strong intensity slopes.
>
>- UPDATES:
>  Unannounced pipeline changes that change object definitions, require
>  changes to the database, that can be time consuming, given the fact,
>  that we have to figure out the changes from the code, and guess
>  the needed Database changes. Usually Danny sends out an e-mail
>  explaining the required changes (usually after talking with Roeland
>  about the changes in the pipeline),  but these e-mail come about 2
>  days after the changes, causing severe interruptions.
>
>  Suggestion: Create a stable branch of the pipeline in the CVS with
>  weekly? updates from a development branch, and the changes in these
>  updates should be discussed with the DBAs before, so that updates to
>  the pipeline cause as few interruptions as possible.
>
>
>
>- TESTS:
>
>  - Bias:
>
>    Subtracting resulting masterbias from its raw input frames
>
>    rawbias file name                       median          stddev          average         stddev
>    seWFI.2003-01-05T20C54C42.283_4.fits    -0.199997       18.876          -0.244914       18.8759
>    seWFI.2003-01-05T20C55C44.983_4.fits    -0.100006       18.9255         -0.161555       18.9254
>    seWFI.2003-01-05T20C56C42.354_4.fits    0.100006        18.89           0.00905352      18.8897
>    seWFI.2003-01-05T20C57C39.851_4.fits    0.100006        18.9164         -0.00907611     18.916
>    seWFI.2003-01-05T20C58C34.232_4.fits    0               18.8818         -0.0418041      18.8818
>    seWFI.2003-01-05T20C59C33.157_4.fits    0               18.881          -0.0651421      18.8809
>    seWFI.2003-01-05T21C00C32.066_4.fits    0               18.8516         -0.0559038      18.8515
>    seWFI.2003-01-05T21C01C33.362_4.fits    0               18.888          -0.0407198      18.888
>    seWFI.2003-01-05T21C02C30.338_4.fits    0.100006        18.8894         0.000104276     18.8891
>    seWFI.2003-01-05T21C03C29.919_4.fits    0.100006        18.9252         0.0489991       18.9252
>
>    (Is there a numerical round-off occurring in the median computation?).
>
>  - DomeFlat:
>
>    Flatfielding biassubtracted raw domeflatframes using the processed
>    domeflat. ( SEM = std. error)
>
>    flatfielded raw flatfield filename          median      stddev          average stddev
>    dseWFI.2003-01-06T21C59C26.278_4.fits       17778.8     90.3731         17778.1 90.3702
>    dseWFI.2003-01-06T22C00C53.969_4.fits       19056.3     94.5017         19055.6 94.4991
>    dseWFI.2003-01-06T22C02C15.050_4.fits       19074.4     94.4472         19073.4 94.4418
>
>  - TwilightFlats:
>
>    Flatfielding biassubtracted raw twilightflatframes using the processed
>    twilightflat. ( SEM = std. error)
>
>    flatfielded raw flatfield filename          median  stddev          average stddev
>    dseWFI.2003-01-04T00C17C43.159_4.fits       17885.3 122.664         17886   122.662
>    dseWFI.2003-01-04T00C19C14.085_4.fits       17161.4 134.724         17161.9 134.723
>    dseWFI.2003-01-04T00C21C01.056_4.fits       16581.6 151.299         16582.4 151.297
>
>  - Astrometry:
>    From visual inspection of stars from the USNO catalog overplotted
>    on the image, the astrometric solution determined by the pipeline
>    seems to be very accurate even out to the edges.
>
>    Hard numbers:
>    mean position differences in arcsec:
>    RA            DEC
>    -0.0002       0.0001
>
>    mean sigma of the position differences in arcsec:
>    RA            DEC
>    0.4199        0.4021
>
>
>
>
>Cheers,
>
>
>Mark
>
>
>
>
>
>=====================================================
>Dr. Mark J. Neeser
>
>Institute for Astronomy and Astrophysics,       _/       _/     _/ _/_/  _/
>Ludwig-Maximilians-Universitaet Muenchen       _/ _/  _/_/     _/ _/ _/	_/
>                                              _/   _/  _/ _/  _/ _/  _/_/
>Scheinerstrasse 1,                           _/       _/   _/_/ _/    _/
>D-81679 Muenchen, Germany
>
>Tel: +49-89-2180-5995
>Fax: +49-89-2180-6003
>
>email:  neeser at usm.uni-muenchen.de
>
>
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