[KIDS] Fwd: KIDS internal release 1.0

[Gijs Verdoes Kleijn]

-------- Original Message --------
Subject: 	KIDS internal release 1.0
Date: 	Tue, 17 Jul 2012 21:22:54 +0200 (CEST)
From: 	Thomas Erben <terben at astro.uni-bonn.de>
To: 	Jelte de Jong <jelte at strw.leidenuniv.nl>
CC: 	verdoes at astro.rug.nl, Oliver-Mark Cordes <ocordes at astro.uni-bonn.de>



Hi Jelte, Hi Gijs,

Oliver transfered some of the KIDS internal release 1.0 images to
Bonn. I did not have time to look into them in any detail but I
already have some general comments on the format of the data. I send
them to you because I cannot make the telecon tomorrow:

- The names are like:

Sci-JMCFARLAND-OMEGACAM-------OCAM_i_SDSS---Coadd---Sci-56019.4351120-a07ff064fd3c0ac0173d358076fdd87149e8f4b4.fits

   I hope that this is not the naming convention we are supposed to work
   with outside AstroWise. There is a mapping between these 'database
   names' and the ones that a non-AW uses gets, right?
   Please avoid special shell characters (such as '-' or '.') in product
   names.
   It can be difficult to batch process such files with shell scripts.
   If you need a separator the underscore '_' turned out to be a good
choice.

- I guess you know that important header keywords such as GAIN and EXPTIME
   seem to be zero everywhere (I did not check all images).

- It is bad to put important information in 'HISTORY'
   keywords.  First, I do not think that keys such as GAIN, EXPTIME,
   SATURATE or EQUINOX should be put in keywords that indicate
   processing history of files. Second it is difficult to automatically
   extract such information with 'standard programs' (e.g. dfits and
   fitsort). Also, SExtrator cannot use these keywords in this way.

- I note that all images seem to have different sizes. To easily
   extract objects in double image mode all data from a specific KIDS
   tile need to have the same image dimensions. In the past, it turned
   out to be useful if all images of a survey have the same size,
   e.g. 20000x20000. This should be large enough.

- The image
Sci-JMCFARLAND-OMEGACAM-------OCAM_i_SDSS---Coadd---Sci-56089.5969610-a09de88023bd4faf27229fdb0e6668249fee5d65.fits

   was obviously created by John. However, the author header keyword says
   'omegacen'. This seems to be the case for all images.

- It seems that your float format for header keywords is not consistent:
   I see e.g.

   Cal-JMCFARLAND-OMEGACAM--- ..	KIDS_49.9_-33.1 	4.990099010E+01
-3.313736264E+01
   Sci-JMCFARLAND-OMEGACAM--- .. KIDS_49.9_-33.1         49.9009901
-33.13736264

   Here you use floating point and exponentials for coordinates.

- Can you tell me the scaling of the image pixels? I see values of around
   10e-11 which seems to be very low to me. It is probably not a
   standard scaling such as 'ADU / s'. Please document the meaning
   in a 'BUNIT' header keyword.

That's it for now. I will have a closer look next week.

     Cheers,
      Thomas




-- 
--------------------------------------------------------------------
|dr Gijs Verdoes Kleijn         |   astronomer                     |
|e-mail: verdoes at astro.rug.nl   |   OmegaCEN / Kapteyn Institute / |
|www: www.astro.rug.nl/~verdoes |   Target                         |
|tel: +31-50-3638326            |   University of Groningen        |
|mobile: +31-654658050          |   postal address:                |
|                               |   Kapteyn Astronomical Institute |
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|                               |   The Netherlands                |
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