[Comm2011] Fwd: PPRS-041683-Updated-VST-INSTRUMENT CONTROL SYSTEM-calibration of the world coordinate system on IA, AG, ... CCDs-Science Operations

[Konrad Kuijken]

Begin forwarded message:

> From: Paranal_AREmail <esoarspl at eso.org>
> Subject: PPRS-041683-Updated-VST-INSTRUMENT CONTROL SYSTEM-calibration of the world coordinate system on IA, AG, ... CCDs-Science Operations
> Date: May 12, 2012 17:52:24 GMT+02:00
> To: kuijken at strw.leidenuniv.nl
> Reply-To: Paranal_AREmail <esoarspl at eso.org>
> 
> Problem number PPRS-041683 in the Paranal PRS has now been updated.
> The new details of the ticket are listed below.
> This is for your information only.
> 
> 
> Problem Number  : PPRS-041683
> 
> Creation Date   : 2011-09-15 06:06:42  by Thomas Szeifert  (vst at eso.org)
> Type            : Comment
> Keywords        : calibration of the world coordinate system on IA, AG, ... CCDs
> Priority        : Necessary
> Deadline        : 
> Status          : Open
> 
> -----  Minor Change Section ---------------------
> 
> -------------------------------------------------
> 
> Location             : VST
> Area/Instrument Type : CENTRAL CONTROL
> System/Instrument    : INSTRUMENT CONTROL SYSTEM
> Sub-system           : INSTRUMENT CONTROL SOFTWARE
> 
> Assigned to Group    : Science Operations
> Assigned to Person   : smieske
> CC List              :
> imunoz at eso.org
> creinero at eso.org
> kuijken at strw.leidenuniv.nl
> 
> par-tios at eso.org 
> uweilenm at eso.org 
> msterzik at eso.org 
> vst at eso.org
> par-vst at eso.org 
> akaufer at eso.org 
> acarlier at eso.orgVst_all
> 
> Telescope Downtime   : 00:00
> Workload (hrs.)      : 0
> Detailed Description :
> I have tried twice to check where the AG stars appear on the OMEGACAM aux AG CCDs after centering on reference pixel (196,178) on the telescope AG. The center of rotation is close to the pixel (196,178) .
> 
> At position angle 0 on the sky the stars appear on too low on both AG CCDs ( you'd like to lower the reference pixel in y for both
> CCDs) in
> Appl_data:OMEGACAM:OCAG:ocagws:control:ocCRPIX_GCCD1
> Appl_data:OMEGACAM:OCAG:ocagws:control:ocCRPIX_GCCD2
> 
> However, if you rotate to 180 degree in the sky you find the stars about 45 pixels toward the right hand side from the  center of the box calculated by the AG.
> 
> I believe that this means that there is about a 22 pixel offset between the center of rotation of the telescope and the instrument which
> could be fixed by an XY-offset to be sent together with the preset (like the xy-offset of VIMOS to center the IFU, or the XY offset of SINFONI of 0.8 arcsecs).
> 
> Once this is done then all the reference pixels of all 4 auxiliar and all 32 science CCDs should be corrected by the same amount
> (sign an size of the offset to be discussed).
> 
> 
> -----  Worklog & Comments Section ---------------
> 
> Worklog and Comments : 
>   2011-09-30 18:30:39   smieske
>      Status Changed: Open 
>      Modified By: smieske 
>      Modified Date: 2011-09-30 18:30:39 
>      Status Changed: Open 
>      Modified By: smieske 
>      Modified Date: 2011-09-30 18:30:39 
>   2012-05-12 15:51:30   vst
>      we did the telescope pointing model with the reference pixel set to the center of rotation, while it is to be kept at the center of the Shack Hartman sensor in normal operations (to get the star on the SH). The pointing does look well at least at rotation 0 degree. TSz
> 
>      Assignee changed: smieske 
>      Modified By: vst 
>      Modified Date: 2012-05-12 15:51:29 
>      Assignee changed: smieske 
>      Modified By: vst 
>      Modified Date: 2012-05-12 15:51:29 
> 
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