[Comm2011] OCAM2 daily log day 3

[John P. McFarland]

Hi Gert,

Thanks for the info.  We will try for z' sky flats this morning.  If we are 
not successful, we will try again tomorrow night.

I will re-observe g'-band (ADC in and out) in known photometric conditions.

There is some ambiguity about the rotator angles now stored in the headers, 
but you can get comparison values from the keywords:

HIERARCH ESO ADA ABSROT START
HIERARCH ESO ADA ABSROT END
HIERARCH ESO ADA POSANG
HIERARCH ESO TEL PARANG START
HIERARCH ESO TEL PARANG END

in the RawFitsData headers (e.g., RawFitsData.get_header_list(), these 
keywords will be in the primary header, index 0).  Be warned that the ADA 
keywords appear no longer to get their values properly.  If you can do your 
investigations with just the parallax angles (PARANG) combining RA, DEC, and 
LST, you will likely have the most consistent result.

Cheers,


-=John


On Fri, 10 Jun 2011, G. Sikkema wrote:

> hi John,
> I tried to analyse the illumination variations in both g and z of this night.
> First of all: the exposures overlap is excellent for the 33 pointings...
> Secondly: we have now 2x more stars in common in each chip for SA107 compared 
> to our previous analysis for SA110, i.e. 61 stars for SA107 and ~30 for 
> SA110.
>
> Currently :
> for z we need to construct a good fringe frame which may be constructed from 
> the 33 pointings. I do not see illumination variations when using a default 
> fringe frame, however, this default frame does not remove most fringes... 
> furthermore we need skyflats in z, I use forever skyflats at this moment
>
> For g: the results look reasonable. One pointing of the 33 likely had cirrus 
> in its field of view because it has an offset of +0.2 mag compared to the 
> others. Please compare  our previous attempt  plot 
> illum_gain_corrected_gband_OCAM1B.jpg with the current  plot 
> illum_gain_corrected_gband_OCAM2.jpg, and note the offset (for chip 87)
>
> The plots show the common stars ~30 for SA110 vs 61 stars in SA107 in each 
> chip.
>
> I am curious what rotator angle was used compared to our previous attempt.
>
>
> cheers,
> Gert S.
>
>
> John P. McFarland wrote:
>> Hi All,
>> 
>> Tonight was quite a productive night.  Unfortunately the Toelner is still 
>> not responding, so no new quick checks (despite the 51 test quick checks) 
>> or 4-angle dome flats.  The problem will hopefully be solved today. 
>> Andrea, Koen, and Dietrich arrived tonight and worked until around midnight 
>> when I took over.
>> 
>> The conditions were relatively good with mostly excellent 0.5-0.7 arcsec 
>> seeing, but somewhat poor transparency.  It is difficult to say which 
>> observations will be photometrically useful.  Several polar field 
>> observations were obtained, so the variable conditions should be seen there 
>> as well.  Complete 32 CCD offset observations in z and g were obtained for 
>> SA107.  These are almost perfect compared to the last nights' sets, but 
>> there was still some very light cirrus visible on the all-sky cam during 
>> these.  Also, please check the 32 CCDs exposures overlap for the center of 
>> the field.  The center was placed on all the CCDs in the order that they 
>> are stored in the RawFitsData.
>> 
>> A donut template was attempted for the VST people (requested by Koen), but 
>> failed due to some template keyword error (Andrea and Koen will have to 
>> investigate this).  Nonetheless, the focus offsets were done and the 
>> required data secured.
>> 
>> Following this, the night was wrapped up with a 3x3 grid from the newest 
>> plate system centered on about the SA113 field, taken with dither,N=5 in r 
>> for 60 seconds per exposure.  Please check these out to make sure all the 
>> offsets were done correctly.
>> 
>> Cheers,
>> 
>> 
>> -=John
>> ------------------------------------------------------------------------
>> 
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>
>
> -- 
> dr. Gert Sikkema
>
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