[Comm2011] Image quality VST

[E. Helmich]

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
>>
> 
> --
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