[Comm2011] Image quality VST

[E. Helmich]

Hey zo'n plot heb ik ook! Ik heb het ook naar Olaf gestuurd.

Ewout

On Mon, 28 Mar 2011 23:05:53 +0200, Gijs Verdoes Kleijn
<verdoes at astro.rug.nl> wrote:
> Hi Ewout,
> 
> I'm led to same conclusions as Edwin. In addition I'm impressed by the
> FWHM=0.6arcsec seeing as minimum. This is in agreement with independent
> measurements (e.g., DIMM)?
> 
> Cheers, Gijs
> ps. FYI, I had a quick look at the rawbias counts for those ingested
> sofar: attached median values vs extension number shown, colored by MJD
> of DATE-OBS. Extension 32 is the odd one out/
> 
> Op 28-3-2011 22:43, helmich schreef:
>> Indeed. There is going to be a meeting tonight with Pietro Shipani, to
>> discuss this. He's been sleeping through most of this since he's been
>> acting Telescope Operator.
>>
>> Ewout
>>
>> On Mon, 28 Mar 2011 22:35:04 +0200, "Edwin A. Valentyn"
>> <valentyn at astro.rug.nl>  wrote:
>>> Hm,
>>>
>>> my first reactions:
>>> - patterns are not what is expected from tilts
>>> - patterns at various rotator positions are at first order remarkably
>>> consistent with each other; so  rotators are not causing effects;
>>> picking out the one with largest amplitude variation is 270deg, which
>>> can be taken as representative.
>>> - at rot 270 FHWM shows allmost spherical function over the field of
>>> view, diameter of circle several degrees; it looks like some overall
>>> misalignment in telescope, (assuming rot 0 corresponds to North) in E-W
>>> direction
>>>
>>> But I guess, you have noted the same and VST people are scratching
> their
>>> head?
>>>
>>> regards
>>> Edwin
>>>
>>> On 28-3-2011 8:30, helmich wrote:
>>>> Hi,
>>>>
>>>> Here are the resulting PSF anisotropy plots for 4 images of the same
>>>> field taken with 0,90,180 and 270 degrees rotator. We think that the
>>>> dominant effect is not a tilt. Beware that the legend denoting
>>>> ellipticity at the bottom is not correct scale.
>>>>
>>>> Regards,
>>>>
>>>> Ewout
>>>>
>>> --
>>>
> -------------------------------------------------------------------------
>>> Prof. Dr. Edwin A. Valentijn       University of Groningen
>>> Coordinator Target                 www   : www.rug.nl/target
>>> Head OmegaCEN                      www   : www.astro.rug.nl/omegacen
>>> Kapteyn Astronomical Institute     tel   : +31 (0)50 3634011/4036
> (secr)
>>> P.O.Box 800                        mobile: +31 (0)6 48276416
>>> NL-9700 AV Groningen               e-mail: valentyn at astro.rug.nl
>>> The Netherlands                    www   : www.astro.rug.nl/~valentyn
>>>
> -------------------------------------------------------------------------
> 
> --
> --------------------------------------------------------------------
> |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 |
> |                               |   Postbus 800, 9700 AV, Groningen|
> |                               |   The Netherlands                |
> --------------------------------------------------------------------
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