[Comm2011] Fwd: PPRS-041987-Updated-VST-INSTRUMENT CONTROL SYSTEM-Strong degradation of IQ, at a position away from Meridian-Instrumentation
Konrad Kuijken
kuijken at strw.leidenuniv.nl
Thu Oct 13 16:49:59 CEST 2011
Begin forwarded message:
> From: Paranal_AREmail <esoarspl at eso.org>
> Subject: PPRS-041987-Updated-VST-INSTRUMENT CONTROL SYSTEM-Strong degradation of IQ, at a position away from Meridian-Instrumentation
> Date: October 4, 2011 23:12:23 GMT+02:00
> To: kuijken at strw.leidenuniv.nl
> Reply-To: Paranal_AREmail <esoarspl at eso.org>
>
> Problem number PPRS-041987 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-041987
>
> Creation Date : 2011-10-04 05:22:24 by Steffen Mieske (vst at eso.org)
> Type : Problem
> Keywords : Strong degradation of IQ, at a position away from Meridian
> Priority : Necessary
> Deadline :
> Status : Assigned
>
> ----- Minor Change Section ---------------------
>
> -------------------------------------------------
>
> Location : VST
> Area/Instrument Type : CENTRAL CONTROL
> System/Instrument : INSTRUMENT CONTROL SYSTEM
> Sub-system : GUIDING AND WFS SOFTWARE
>
> Assigned to Group : Instrumentation
> Assigned to Person : mriquelm
> CC List :
> kuijken at strw.leidenuniv.nl
> ikastine at eso.org
> nhaddad at eso.org
> Andrea.Baruffolo at oapd.inaf.it
> par-tios at eso.org
> uweilenm at eso.org
> msterzik at eso.org
> vst at eso.org
> par-vst at eso.org
> acarlier at eso.org
> akaufer at eso.org
>
> Telescope Downtime : 00:51
> Workload (hrs.) : 0
> Detailed Description :
> Hello,
>
> we experienced tonight a repeated degradation of IQ around 04:22 UT and 05:06 UT, see e.g.
>
> /home/astro/awehome/cache/OMEGACAM_IMG_OBS277_0066.psfanisotropy.png and
> /home/astro/awehome/cache/OMEGACAM_IMG_OBS277_0071.psfanisotropy.png
>
> I submit as a separate ticket to PPRS 041986, since we were well away from the meridian.
>
> The first occurence was when guiding with 2 stars, the 2nd occurence when guiding with a single star. It is unclear to what this is related, since it was framed by images of the same sequence which were fine. During the 2nd occurence the OCAM IA did indeed measure a defocus of about 1000 units, which it then corrected during the readout.
>
> Below the list of IQ measurements by the pipeline. The IQ degradation is the third column from the right. Note the values around 1.3 at the start (bad) and the 1.5 around 04:51 (very bad). 1.0 would be a flat image.
>
> 2011-10-04T04:17:21.439 581461 i_SDSS 0.96 0.10 0.90 0.11 0.97 0.13 1.52 0.25 1 1.07 1.31 0.13 8
> 2011-10-04T04:22:06.282 581461 i_SDSS 0.97 0.10 0.89 0.12 0.96 0.15 1.53 0.26 1 1.08 1.33 0.14 8
> 2011-10-04T04:26:46.604 581461 i_SDSS 0.95 0.07 0.87 0.09 0.94 0.12 1.46 0.23 1 1.05 1.33 0.12 8
> 2011-10-04T04:37:09.271 581461 i_SDSS 0.71 0.08 0.68 0.05 0.69 0.04 0.72 0.10 0 0.69 1.02 0.07 8
> 2011-10-04T04:41:53.803 581461 i_SDSS 0.71 0.03 0.69 0.07 0.69 0.07 0.72 0.06 0 0.69 1.01 0.06 8
> 2011-10-04T04:46:38.816 581461 i_SDSS 0.67 0.04 0.66 0.08 0.66 0.07 0.71 0.06 0 0.66 1.01 0.06 8
> 2011-10-04T04:51:22.669 581461 i_SDSS 1.07 0.10 0.70 0.09 0.73 0.08 1.22 0.14 0 0.90 1.53 0.10 8
> 2011-10-04T04:57:01.752 581461 i_SDSS 0.73 0.04 0.76 0.05 0.76 0.06 0.75 0.06 0 0.74 0.86 0.96 1.19 0.05 0.09 8
>
>
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------
> Date OBid Filter | ImaQuality Ellipticity | N_Ell | MeanIQ | IQ_degr | MeanELL | N_reduced
> | Chip65 Chip76 Chip85 Chip96 | | Ima OB/F | Ima OB/F | Ima OB/F |
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
> ----- Worklog & Comments Section ---------------
>
> Worklog and Comments :
> 2011-10-04 06:21:33 vst
> The IA integration time was 15s instead of the usual 30s, because we had tested manual IA earlier in the night. I am not sure if this lower time is sufficient enough to cause erratic corrections to be sent. I include Andrea Baruffolo in CC.
> -Steffen
>
> Assigned to Group Changed: Software
> Modified By: vst
> Modified Date: 2011-10-04 06:21:33
> Assigned to Group Changed: Software
> Modified By: vst
> Modified Date: 2011-10-04 06:21:33
> 2011-10-04 12:52:44 gvaldes
> assigned to instrumentation, just to crosscheck with astronomer about probables causes of the problem.
>
> Regards
> GVA
>
> Assignee changed: mriquelm
> Assigned to Group Changed: Instrumentation
> Status Changed: Assigned
> Modified By: gvaldes
> Modified Date: 2011-10-04 12:52:44
> Assignee changed: mriquelm
> Assigned to Group Changed: Instrumentation
> Status Changed: Assigned
> Modified By: gvaldes
> Modified Date: 2011-10-04 12:52:44
> 2011-10-04 21:09:54 vst
> Adding Konrad Kuijken in cc.
>
> I copy&paste below the aberration corrections sent by OmegaCAM during the affected time of the large image quality degradation. In the line like "WRTABER 0 44.4 0.0 0 0 -154", the first nonzero number is the focus correction, and the second nonzero number is the coma correction. Values <~150-200 for focus indicate stable conditions, and values ~<300 for coma.
>
> Note that for the first instance of IQ degradation (after UT 04:21), a large coma correction of -519.1 is sent _before_ the affected science exposure.
>
> For the second instance (UT 04:50), a large focus correction of -1020.5 is sent _before_ the affected science exposure, and in the next instance this focus offset is corrected back by sending +1054. This clearly explains the IQ degradation in the second instance. The question is why this apparently erroneous focus offset was calculated in the first place.
>
> Andrea or Konrad, do you have a judgement on this? Can it be that the lower IA loop time of 15s instead of 30s is increasing strongly the probablity of spurious aberration measurement?
>
>
> Oct 4 04:02:37 wocam seqWish: 2011-10-04 04:02:37.313213 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:07:15 wocam seqWish: 2011-10-04 04:07:15.742152 wocam seq bob_21460 199 0 about to send WRTABER 0 44.4 0.0 0 0 -154.1 0 -8.6 0 0 -3.2 0 0.0 0 0 0 0 0, 0 0 0 0 0 -120.2 0 20.5 0 0 143.2 0 0.0 0 0 0 0 0
> Oct 4 04:07:22 wocam seqWish: 2011-10-04 04:07:22.149524 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:21:24 wocam seqWish: 2011-10-04 04:21:24.803730 wocam seq bob_21460 199 0 about to send WRTABER 0 -39.1 0.0 0 0 -519.1 0 -42.1 0 0 -12.9 0 0.0 0 0 0 0 0, 0 0 0 0 0 98.3 0 166.8 0 0 72.8 0 0.0 0 0 0 0 0
> Oct 4 04:21:31 wocam seqWish: 2011-10-04 04:21:31.224732 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:26:08 wocam seqWish: 2011-10-04 04:26:08.486148 wocam seq bob_21460 199 0 about to send WRTABER 0 28.5 0.0 0 0 -227.6 0 -52.3 0 0 -7.1 0 0.0 0 0 0 0 0, 0 0 0 0 0 -53.3 0 95.1 0 0 -58.1 0 0.0 0 0 0 0 0
> Oct 4 04:26:13 wocam seqWish: 2011-10-04 04:26:13.884911 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:30:50 wocam seqWish: 2011-10-04 04:30:50.052357 wocam seq bob_21460 199 0 about to send WRTABER 0 -67.1 0.0 0 0 -266.5 0 -57.9 0 0 -17.4 0 0.0 0 0 0 0 0, 0 0 0 0 0 -11.7 0 123.0 0 0 -53.5 0 0.0 0 0 0 0 0
> Oct 4 04:30:56 wocam seqWish: 2011-10-04 04:30:56.462539 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:41:11 wocam seqWish: 2011-10-04 04:41:11.820094 wocam seq bob_21460 199 0 about to send WRTABER 0 41.0 0.0 0 0 -104.8 0 -52.5 0 0 -45.2 0 0.0 0 0 0 0 0, 0 0 0 0 0 136.1 0 157.2 0 0 70.3 0 0.0 0 0 0 0 0
> Oct 4 04:41:18 wocam seqWish: 2011-10-04 04:41:18.222864 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:45:57 wocam seqWish: 2011-10-04 04:45:57.005820 wocam seq bob_21460 199 0 about to send WRTABER 0 -45.2 0.0 0 0 -130.5 0 -20.6 0 0 -23.4 0 0.0 0 0 0 0 0, 0 0 0 0 0 -142.7 0 138.9 0 0 53.2 0 0.0 0 0 0 0 0
> Oct 4 04:46:02 wocam seqWish: 2011-10-04 04:46:02.409572 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:50:41 wocam seqWish: 2011-10-04 04:50:41.295085 wocam seq bob_21460 199 0 about to send WRTABER 0 -1020.5 0.0 0 0 -245.1 0 -66.2 0 0 -15.6 0 0.0 0 0 0 0 0, 0 0 0 0 0 -175.2 0 9.7 0 0 56.2 0 0.0 0 0 0 0 0
> Oct 4 04:50:46 wocam seqWish: 2011-10-04 04:50:46.692037 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 04:55:25 wocam seqWish: 2011-10-04 04:55:25.942347 wocam seq bob_21460 199 0 about to send WRTABER 0 1054.5 0.0 0 0 -281.0 0 -38.5 0 0 -20.6 0 0.0 0 0 0 0 0, 0 0 0 0 0 135.3 0 124.6 0 0 -130.1 0 0.0 0 0 0 0 0
> Oct 4 04:55:32 wocam seqWish: 2011-10-04 04:55:32.354534 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 05:01:05 wocam seqWish: 2011-10-04 05:01:05.048519 wocam seq bob_21460 199 0 about to send WRTABER 0 -122.0 0.0 0 0 -421.7 0 -48.5 0 0 -12.4 0 0.0 0 0 0 0 0, 0 0 0 0 0 -70.4 0 -163.2 0 0 -14.5 0 0.0 0 0 0 0 0
> Oct 4 05:01:11 wocam seqWish: 2011-10-04 05:01:11.487487 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oct 4 05:15:45 wocam seqWish: 2011-10-04 05:15:45.133406 wocam seq bob_21460 199 0 about to send WRTABER 0 47.8 0.0 0 0 -198.6 0 -38.0 0 0 -26.2 0 0.0 0 0 0 0 0, 0 0 0 0 0 79.2 0 104.2 0 0 100.3 0 0.0 0 0 0 0 0
> Oct 4 05:15:51 wocam seqWish: 2011-10-04 05:15:51.541734 wocam seq bob_21460 199 0 WRTRABER returned 0
> Oc
>
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